Why don't monsters break the game?

[gogogome]

Efreetis, Zodars, Pit Fiends, Glabrezus, Solars, etc. with their free wishes can make at-will wish items with infinity xp built in per cast.
Sarrukhs, mirror mephits, etc. also have similarly broken abilities that can end the world within a round or two.

So why don't monsters break the game? Why do we meet Efreetis or Glabrezus not fully decked out in epic magic items?

If there is some reason for this, then I think I can make PCs adhere to this reason as well and unban some content.

There's a few posts about mirror mephits that surfaced recently and I could see them working in the hands of a PC when they're not abused, which gave me the idea for this thread. What incentive is there for monsters to not break the world?

[NigelWalmsley]

In RAW, you really can't. There isn't a good reason why Solars don't start every fight with a Solar Cascade, or why Efreet don't trade Wishes to get a free magic item of their choosing every day, or why no one has Mirror Mephit'd up an infinite army of mini-mes. Those abilities break the game. You can't even rely on MAD, because they offer a big enough first-mover advantage that you can't rely on deterrence (not to mention the apocalypse cults for whom "mutual destruction" is the goal).

If you massage RAW slightly so that Wish no longer spits out unbounded power, the answer is that they do those things, and that's how they get their crazy extraplanar architecture. The Efreets didn't build the City of Brass by hand, they wished it into being. The gilded halls of the celestials are maintained by whole armies of Solar architects. And so on and so forth. I personally think that kind of thing is pretty compelling, and it gives you a built in reason why they aren't crapping all over the Prime: what can a bunch of faux-medieval peasants do for beings that can create anything they desire with a thought?

[Quertus]

Because Pun-Pun won't let them.

Whenever they would think to do something that incredibly stupid, instead, they don't.

Or maybe Pun-Pun is less proactive, and, instead, whenever someone does something like that, he blows up the universe, then rebuilds it, just without them / with a less dumb them in it.

[Gauntlet]

Wish: The fact it allows for an arbitrarily expensive item to be created on the fly is something that you'd just have to houserule away. Once there's a reasonable limit on the amount of value that can be generated in a casting, and you can avoid having it go infinite, it's just a powerful tool which is likely primarily used as a way of reinforcing territory and defenses, or otherwise entrenching the existing factions rather than exponentially taking control of the multiverse.

Solar Chain Gates: Gate literally calls another Solar from somewhere else in the multiverse. Unless there's something particularly problematic right in front of them, pulling another Solar away from whatever their current duties are probably doesn't actually benefit the forces of Good in a meaningful enough manner for a Solar to use it often. It means that the Solars can concentrate all their power into a single point if they need to, but that's it. Probably mostly useful for defending critical planar infrastructure, which helps to explain why the heavens haven't yet been defeated by the infinite numbers of the various evil factions.

Mirror Mephits: You could have some sort of authority which stops the Mephits from creating excessive numbers of copies of things, whether powerful Mephits with class levels who don't want to draw undue attention from the rest of reality, other outsiders, or a deity. You could place some sort of limiter on the ability of a rogue mephit to go exponential - whether by weakening simulacrum, making 2HD Mephit Simulacrums unable to use the ability, or by restricting their simulacrum ability to make copies of themselves or specific other creatures (like their master, if a familiar) only.

[Telonius]

For whatever reason, most monsters are poor compared to level-appropriate PCs; the typical ECL 20 encounter yields about 80,000 gp (http://www.d20srd.org/srd/treasure.htm#monstersWithTreasure). So for most monsters, that's going to severely limit how many shenanigans they're able to pull as far as magic items go.

For the monsters with game-breaking abilities (Solars, Efreeti, and the like) the answer has to come down to one of a few: either nobody's thought of it yet; or they actually can't; or they can but there's a very good reason they don't; or they already have and we're living in the aftermath (may overlap with "good reason they don't").

[Buddy76]

D&d is not a coherent, closed simulation of a world. It's a toolbox for people to colaborate and create their own stories. Ideally, a good DM conjures up the illusion of a fully fledged world that exists and runs regardless of the players, but it's ultimately that, an illusion. The players are at the forefront and the world is there for them to react to and intercact with.

If you need justification to some monster not breaking the setting, you can provide your own. For example, Solars, Pit Fiends and Glabrezus are usually bound to higher powers (Deities, Archfiends, etc) and might not be able to use their wish abilities whitout permission from those powers. Zodar are constructs of unknown creation, so maybe whatever created them left some very specific condititions under which they can use wish (I think their entry even mentions that they only use this ability once every century or so, even though they can cast it once a year).

But yeah, trying to build a functional world from RAW alone will yield absurdities because the system was not designed for that.

[Droid Tony]

The real life answer is that most DMs don't break the game.

In 3.5E and Pathfinder you don't find many 'universe' type rules. Unless you count the vague rules that say the DM can just make whatever they want. Older editions of D&D at least had some universe type rules.

The basic idea is the multiverse has both natural and artificial checks and balances.

For natural ones it is things like using a lot of magic in one place at one time creates a disruption. It might attract creatures, maybe even magic eating creatures, create a magic storm, create a magic dead zone or dozens of other things.

Artificial ones are simply creatures that watch and take action.

So if a single creature used a ton of wishes, they might trigger a magic storm that forever drains their magic or summon an epic creature that will kill them.

[Telonius]

For the Efreeti: exercising phenomenal cosmic power gets boring after a while. You can have everything you ever wanted, but so can everybody else in your society. Gold becomes as valuable as a cobblestone, magic is as common as sand. Sure, you could go out and conquer, but what would be the point? Ruling a bunch of lesser beings might give an ego boost for a bit, but when you don't have a defined lifespan even that gets tiresome after a century or two.

[False God]

Because they can't risk using their powers at all in case a bunch of adventurers pop out of nowhere and want to fight them. So they sit around all day like bored teenagers at a grocery store waiting for something to happen.

Because the universe isn't a "game" to them and "breaking the game" represents very real damage to reality.

Because they know more loot means bigger target for adventurers.

Because anything beyond what is explicitly stated in the rules-text of "Wish" requires DM approval and since none of them are players, none of them have a DM, so they can't do that.

[exelsisxax]

Glabrezu and efreet can't use wishes themselves, they must be given to some other entity. Not sure how specific efreet is, but glabrezu requires a mortal humanoid, and mentions how they fulfill it in the most destructive way possible. That doesn't break the game at all, it is fully consistent with the game and its setting. Zodar get to use their wish upon dying, so it's not like they have any to spare.

A lot of the rest... yeah, once you start fighting big demons those solars are definitely going to Gate their friends in to help. But the demons/devils are also going to be chain summoning, so enjoy your new eternal war! RAW really breaks things quick.

[gogogome]

I think there's something here.

All monsters don't want to use these game breakers because... they just don't want to. It's an instinct. Just like how humans that don't eat vegetables because they don't want to no matter how good it is for them, these guys don't want to use wish on themselves because they don't want to. It doesn't matter how much it makes them stronger, they just don't want to.

Mirror mephits don't make a simulacrum army because they don't want to. They just don't. So they only use it in combat to make a clone of whatever they're fighitng.

Hardwired intense dislike. And they don't like others using it either so when they learn pcs are abusing it they get to together to cap his ass because they're hardwired to not like PCs who use wish or some other thing.

[Clementx]

Or you can accept that a lot of monsters and setting details are written to follow existing fantasy tropes/stories, like wish-granting genies and demons. Until a DM introduces them, they don't exist, and when he does, the DM sets the context. If he sets an abusable one, it is part of the game for everyone to agree that nothing world ending is actually intended. TO isn't what most tables are really doing.

Also, sometimes monsters just have poorly written abilities, and the same solution applies.

[HouseRules]

Old School -- If the players are not smart enough, they will die repeatedly.
New School -- DM's are thought to lose the game to players.

[gogogome]

Old School -- If the players are not smart enough, they will die repeatedly.
New School -- DM's are thought to lose the game to players.

Here I am trying to unban efreetis and mirror mephits for my players and...
I don't understand what this person is trying to say.

[NigelWalmsley]

Hardwired intense dislike. And they don't like others using it either so when they learn pcs are abusing it they get to together to cap his ass because they're hardwired to not like PCs who use wish or some other thing.

I don't think that's a good idea. Imagine, for a second, a different perspective. Instead of figuring out how to fix the spells that exist, consider how you might go about implementing those spells. Suppose Genies and Wish didn't exist, and you decided you wanted to be able to do Aladdin, so you wrote them in. There are a lot of ways you could do that, but is the one you want really "you could technically get infinite power, but you'll probably get punked by a bunch of Genies instead"?

[Telok]

Here I am trying to unban efreetis and mirror mephits for my players and...
I don't understand what this person is trying to say.

Old style: Efreet are sociopathic ego-maniacs who want anyone strong or cunning enough to get their wishes to suffer and die. If the wishes aren't very carefully worded...

Current style: Efreet are a level appropriate challenge for X level PCs that will use 20% of their daily resources. The PCs do nonlethal damage to KO it. They buff up and roll a diplomacy check when it wakes up. The game is set up for the players to win as long as they aren't willfully incompetent.

[Warmjenkins]

For efreeti at least I always saw it as the cannot use the wish themselves and never trust anyone enough to give them or even sell them the wish. That they would always be worried that whoever received the wish would somehow use it to force them into eternal servitude through a carefully worded wish.

I actually have a major plot point in the campaign I'm running based upon just such a scenario. An otherwise underwhelming npc managed to get a wish from an efreeti who was (for story and setting reasons) stranded on the material plane. He was supposed to wish him back to the elemental plane of fire and the efreeti figured even if he didn't that he'd be able to twist the wording of the wish in order to achieve that result. However the guy turned out to be far more clever than he appeared and managed to wish the efreeti into servitude and now is just living it up as the ruler of his own empire with 3 free wishes a day so long as he manages to keep wording them carefully enough.

[Jay R]

The real life answer is that most DMs don't break the game.

Absolutely correct. I decide what the NPCs in the world I create will do. I do not choose to destroy my own game.

That’s the meta-reason. The in-world reason I would give if anybody asked would be, “That’s a good question. Who is your PC asking?”

[And if somebody devoted serious time and resources to the question, they would eventually learn that there is a reason that is so alien to human(oid) thought that it would be impossible for them to comprehend it.]

I learned in mathematical simulations class that any simulation will break down if you focus on the part of the system that you weren’t trying to simulate. The answer is to let the simulation do its job, and don’t apply it to the part of the system it wasn’t built to simulate .

In this case, it means don’t use rules in ways that will destroy the game. For some reason, they can’t or don’t use wishes that way. No further explanation will improve the game in any useful way.

[TinyMushroom]

If you want a headcanon, it could either be that such powerful beings have made a pacts, or have superiors that made a pact, not to interfere in the mortal world too much they tear it apart through their war (like the gods in Order of the Stick agreeing to only act through their clerics).

Or perhaps beings who have power of such magnitude don't think on our scale (relative to them, we are insects, and while it's fun to mess around with insects for a bit you're gonna get more enjoyment out of interacting with fellow humans). For most outsiders, the worst thing they can imagine is being enslaved or banished for a few years. It may be inconvenient, but then it could simply be that they don't go around wearing magic items for the same reasons you don't go around in full tactical armor all the time. They just can't imagine a mortal can do something truly bad to them.

A third option is that such powerful beings fight against each other all the time, but because they spend a lot of energy on thwarting each other the material plane ends up in a delicate balance of power. Maybe a Solar doesn't spend any wishes on making items because he constantly has to go around countering Pit Fiends' wishes.

Though, in the end, it really just comes down to "because it'd be awful boring if every setting was an uber high magic tippyverse"

[rrwoods]

I see “wish allows you to create an arbitrarily expensive item” at least once in this thread but I don’t think that’s true. You have to pay XP proportional to the cost of the item you wish for, and there’s a limit to how much XP you can spend at once.

[HeraldOfExius]

I see “wish allows you to create an arbitrarily expensive item” at least once in this thread but I don’t think that’s true. You have to pay XP proportional to the cost of the item you wish for, and there’s a limit to how much XP you can spend at once.

Unless you're using a wish SLA instead of casting it. Then it's free.

As for why monsters don't break the game, I would say that it's because most games that devolve into the DM flaunting high optimization strategies against the players probably don't last for more than a couple sessions at most. The exceptions typically being those games where the players are operating on the same level, but there are less games at that level of optimization than there are discussions about them.

[Bartmanhomer]

Only deities break the game, not monsters.

[Jack_Simth]

Efreetis, Zodars, Pit Fiends, Glabrezus, Solars, etc. with their free wishes can make at-will wish items with infinity xp built in per cast.
Sarrukhs, mirror mephits, etc. also have similarly broken abilities that can end the world within a round or two.

So why don't monsters break the game? Why do we meet Efreetis or Glabrezus not fully decked out in epic magic items?

If there is some reason for this, then I think I can make PCs adhere to this reason as well and unban some content.

There's a few posts about mirror mephits that surfaced recently and I could see them working in the hands of a PC when they're not abused, which gave me the idea for this thread. What incentive is there for monsters to not break the world?

You'll want some house rules and/or social constructs.

Here's a couple ideas to get you started:

Spell-like or Supernatural Abilities: Do not come with "extra" components, just the base effects. Thus:
Wishes: Sure, a Solar or an Efreeti in Wish... but those are limited to the standard 5,000 xp cost, which is fine for washing away afflictions, getting bodies for Resurrection, and the odd bit of 25k diamond creation... but isn't any good for making a Cloak of Resistance.
Chain-gating via Sp or Su abilities: It doesn't come with the optional XP component, and is just useful for planar travel.
Chain-gating via spells: Then the XP component applies, doesn't it? The amount of XP a given creature has available is up to the DM.

[Biguds]

Greetings!

In Pathfinder Adventure Path "Legacy of Fire" and Starfinder Aventure Path "Dawn of Flame" we have examples of efreet using wishes in more vague ways than the hard-coded spell description and.. well, they use a lot of wishes (A LOT) for "plot effects".

But the strength of the wish seems to depend on the strength of the user (not Just HD or CR, but a cosmic scale thing?).

I'd recomend a look there to see how game writers / designers expect to run "plot-spell-using-monsters".

[gogogome]

I'm not looking for meta reasons, i'm looking for lore reasons.

It seems the consensus here is there is none, and house rules are the way to go.

Another thread on this forum gave me a different idea on how to handle this without house rules so I'm gonna unban all previously banned creatures at my table and see how it goes.

[aerilon]

I'd like to add my voice to those whose answers are some form of essentialism.

Basically, it boils down to they don't break the game because it would break the game. There is no in-game lore reason I've seen, or at least not one that's consistent (I think some adventures, fiction books, or other settings touched on/hinted at the existence of some cosmological/universal rules settings type fluff, but I don't have enough personal knowledge to give an in-depth accounting of them) enough to count for our purposes lore-wise.

So the real reason isn't in-game lore. The reason is meta - the characters that are "internal" to the game, like NPCs and monsters, don't break the game because it would break the game. PCs, on the other hand, being "external" in that they are controlled by the players, can break the game in a whole host of ways. How many of which you'll allow is up to you.

[HeraldOfExius]

I'm not looking for meta reasons, i'm looking for lore reasons.

"Breaking the game" is a meta concept. Do you need a lore reason for why monks exist? Should there be some cosmic explanation for why the world isn't populated entirely by wizards, clerics, and druids?

Not everybody is trying to be perfect. Since actual people are able to enjoy playing characters that aren't able to tear apart reality at will, then maybe most monsters that could do so are also content with not doing it.

[JNAProductions]

"Breaking the game" is a meta concept. Do you need a lore reason for why monks exist? Should there be some cosmic explanation for why the world isn't populated entirely by wizards, clerics, and druids?

Not everybody is trying to be perfect. Since actual people are able to enjoy playing characters that aren't able to tear apart reality at will, then maybe most monsters that could do so are also content with not doing it.

An issue with that is it takes only one, or at most a small handful, who DO want to to break the game wide open.

[Bohandas]

Zodars are mindless and can't really use their wish unless it fits their current mission, and Pit Fiends and Efreeti are lawful evil and probably support the establishment

[magic9mushroom]

Efreetis, Zodars, Pit Fiends, Glabrezus, Solars, etc. with their free wishes can make at-will wish items with infinity xp built in per cast.
Sarrukhs, mirror mephits, etc. also have similarly broken abilities that can end the world within a round or two.

So why don't monsters break the game? Why do we meet Efreetis or Glabrezus not fully decked out in epic magic items?

If there is some reason for this, then I think I can make PCs adhere to this reason as well and unban some content.

There's a few posts about mirror mephits that surfaced recently and I could see them working in the hands of a PC when they're not abused, which gave me the idea for this thread. What incentive is there for monsters to not break the world?

The answers you are going to get are along the lines of "the devs never intended SLA Wish to break the game in half and therefore didn't account for it".

There are some vague hints scattered through various books that SLAs that would cost XP if they were spells do actually have some kind of cost attached, which immediately solves the issue for the monsters (though not necessarily for the players abusing the monsters). Not really sure why the devs never chose to make an explicit rule patch.

[afroakuma]

The 2E book Secrets of the Lamp alluded to a lore reason why efreet don't run around spamming wish - they aren't actually personally granting wishes. Rather, their invocation of wish is administrated by the Great Sultan of the Efreet - picture the genie personally flying out to retrieve the Sword of Kilgoblyn from the cavern where it was once lost, or hunting down your enemy to whack him with a scimitar until he falls down very dead. The Sultan could veto and twist any wish issued that he felt went against his own interest and those of his people writ large, but for the most part the actual wish served as the verbal covenant that someone had extracted service from an efreeti. In essence, if your PC wants to play an efreeti, part of their cultural background is understanding what it means for a wish to be fulfilled and how that will be accounted for on the back end.

As for mirror mephits, there's unfortunately very little lore on the Plane of Mirrors for us to draw from, but the little that there has been suggests no small degree of xenophobia and a rather alien attitude toward the un-reflected. The "mirror magic" that a mirror mephit draws upon may come with concerns about creating too many reflections at a time, especially where the quality of those reflections may vary (the Disguise check). Mirroring certain powerful or otherworldly beings would almost certainly come with the risk of drawing the attention and ire of the originals toward the Plane of Mirrors, which has a substantial interest in keeping powerful outsiders out. Even attempting to mirror a powerful servant of a deity would trip the deity's portfolio sense.

[Psychoalpha]

So why don't monsters break the game? Why do we meet Efreetis or Glabrezus not fully decked out in epic magic items?

In an infinite multiverse of possibilities, monsters do break the game, we just happen to be playing in ones where the wave form has collapsed into 'didn't break the game'.

Honestly though, these worlds aren't simulations, they're sandboxes. You might as well ask why red dragons ever get killed by CR appropriate adventurers when they have tools at their disposal that should actually make that whole 'CR appropriate' thing a joke: Because it's called Dungeons and Dragons and an epic fight against a dragon that you actually stand a chance of winning is kind of the point.

Asking why monsters don't break the game is like asking where GTA gets an infinite supply of pedestrians from. I mean surely someone would have depopulated the city by now, right? Except they don't because that's not the game you're playing.

I mean... your players COULD show up to the game and say they've decided they just want to settle down and be farmers and ignore all the adventure hooks, but they don't (I mean, I assume they don't.) because that's not the game you all showed up to play. Likewise, infinite wish spamming overlord outsiders isn't the game you all showed up to play either (except when it is).

Which brings us back to:


If there is some reason for this, then I think I can make PCs adhere to this reason as well and unban some content.

You can't MAKE the PCs do anything. You can sit down and talk to them about the game you all showed up to play, and ask that nobody take things too far in a direction that's going to break the game, and settle on what exactly that means as a group and as a DM. I've said this many times already, but once more for the cheap seats: If the only reason your players aren't breaking your game is because you're banning content, the problem is your players and it needs to be addressed as such.

[nedz]

Deus ex machina — literally.

There are a large number of gods running around who are quite capable of quashing any such nonsense.

And, when someone tries: you get an epic plot.

[aerilon]

Deus ex machina — literally.

There are a large number of gods running around who are quite capable of quashing any such nonsense.

And, when someone tries: you get an epic plot.

That's a pretty summation of "Die Vecna Die!" actually.

[gogogome]

Deus ex machina — literally.

There are a large number of gods running around who are quite capable of quashing any such nonsense.

And, when someone tries: you get an epic plot.

Hey that's actually not a bad idea! Why didn't I think of it?

Deities are threatened by pun-pun, so if anything even looks like it's going down that route they smite them, so all the wish monsters use their SLA as little as possible in fear of incurring a divine smiting.

[magicalmagicman]

Hey that's actually not a bad idea! Why didn't I think of it?

Deities are threatened by pun-pun, so if anything even looks like it's going down that route they smite them, so all the wish monsters use their SLA as little as possible in fear of incurring a divine smiting.

That's actually similar to the plot of Pillars of Eternity.

The gods were created by man, and they actively ban/outlaw animancy (study of manipulating souls) to prevent mortals from figuring out their true origins.

[Psyren]

D&d is not a coherent, closed simulation of a world. It's a toolbox for people to colaborate and create their own stories. Ideally, a good DM conjures up the illusion of a fully fledged world that exists and runs regardless of the players, but it's ultimately that, an illusion. The players are at the forefront and the world is there for them to react to and intercact with.

If you need justification to some monster not breaking the setting, you can provide your own. For example, Solars, Pit Fiends and Glabrezus are usually bound to higher powers (Deities, Archfiends, etc) and might not be able to use their wish abilities whitout permission from those powers. Zodar are constructs of unknown creation, so maybe whatever created them left some very specific condititions under which they can use wish (I think their entry even mentions that they only use this ability once every century or so, even though they can cast it once a year).

But yeah, trying to build a functional world from RAW alone will yield absurdities because the system was not designed for that.


Because they can't risk using their powers at all in case a bunch of adventurers pop out of nowhere and want to fight them. So they sit around all day like bored teenagers at a grocery store waiting for something to happen.

Because the universe isn't a "game" to them and "breaking the game" represents very real damage to reality.

Because they know more loot means bigger target for adventurers.

Because anything beyond what is explicitly stated in the rules-text of "Wish" requires DM approval and since none of them are players, none of them have a DM, so they can't do that.


Absolutely correct. I decide what the NPCs in the world I create will do. I do not choose to destroy my own game.

That’s the meta-reason. The in-world reason I would give if anybody asked would be, “That’s a good question. Who is your PC asking?”

[And if somebody devoted serious time and resources to the question, they would eventually learn that there is a reason that is so alien to human(oid) thought that it would be impossible for them to comprehend it.]

I learned in mathematical simulations class that any simulation will break down if you focus on the part of the system that you weren’t trying to simulate. The answer is to let the simulation do its job, and don’t apply it to the part of the system it wasn’t built to simulate .

In this case, it means don’t use rules in ways that will destroy the game. For some reason, they can’t or don’t use wishes that way. No further explanation will improve the game in any useful way.

^ Some combination of these three, plus a dash of the original background lore afroakuma helpfully supplied.

As a sidenote, I strongly recommend PF Wish; as it (a) removes magic items from the "safe list" which cuts a lot of the abuse, and (b) establishes that not all wishes are equal - with wishes from items, bound creatures, and a caster's own power all having different degrees of general effectiveness, being slanted by the being's outlook in the second case, and overall susceptibility to screw.

[Yahzi Coyote]

What incentive is there for monsters to not break the world?
You left out the famous Shadowclypse. :smallbiggrin:

In my world XP is a tangible resource, like gold. Hence there are no free wishes (somebody has to pay the XP cost for them) and Shadows need to collect enough XP to create another CR 3 creature to spawn.

The source of XP is intelligent minds. So powerful creatures have vast farms of low-level sentient slaves whose primary purpose is to be farmed for XP after they've raised the next generation. These powerful creatures are called "kings." (The bad ones work their peasants into an early grave and the good ones wait till they die of old age.)

This not only solves the problem of why monsters don't take over the world, it also explains why monsters hunt humans (which would otherwise be a terrible food source), why high-level characters have kingdoms that they protect, and why the king is always the toughest guy in town.

Seriously, XP as a material resource solves so many problems, it's like they always meant for it be like that. They even established the price - 1 XP = 5 gp - right there in the DMG.

(Check out Lords of Prime on DriveThruRPG for how this all works.)

[Tedective]

If there was a society where everybody could cast wish 3 times per day for free; chances are they wouldn't. Well, they wouldn't after a while; because some people would use their wishes to seize other peoples' gained resources and ultimately, lives / thoughts.

Wish would be a djinn's greatest weapon and strongest defense against other djinns. A djinn with 3 wishes is infinitely more powerful than a djinn with just 2, and I'm sure they all know that.

[The Insanity]

They do, most DMs just choose to Rule Zero it.

[Willie the Duck]

For the monsters with game-breaking abilities (Solars, Efreeti, and the like) the answer has to come down to one of a few: either nobody's thought of it yet; or they actually can't; or they can but there's a very good reason they don't; or they already have and we're living in the aftermath (may overlap with "good reason they don't").

D&d is not a coherent, closed simulation of a world. It's a toolbox for people to colaborate and create their own stories.

Basically, it boils down to they don't break the game because it would break the game. There is no in-game lore reason I've seen, or at least not one that's consistent (I think some adventures, fiction books, or other settings touched on/hinted at the existence of some cosmological/universal rules settings type fluff, but I don't have enough personal knowledge to give an in-depth accounting of them) enough to count for our purposes lore-wise.

So the real reason isn't in-game lore. The reason is meta - the characters that are "internal" to the game, like NPCs and monsters, don't break the game because it would break the game. PCs, on the other hand, being "external" in that they are controlled by the players, can break the game in a whole host of ways. How many of which you'll allow is up to you.

Splitting the difference here, I think the answer that speaks to me would roughly be: 'D&D, as published, is a set of rules and a just-barely-coherent (including no small amount of inconsistency) implied setting designed to be taken by groups, made their own (in no small part by filling in the lore gaps with how they want the game to work), and play a very player-facing game with it. Mind you, the world should still make sense, or else the players will feel that their characters aren't really wandering around in a world, so much as being at the foot of a conveyor belt that feeds parts of a world to them. However, there's not reason for the explanations for how the world makes sense not to be campaign-specific. Gary stated early one how surprised he was that people wanted to know what his game world was like. Not that that stopped him from selling it to us, but there are clearly spots from the up through 3e (and past) where the explanations for why X doesn't Y isn't 'well there clearly needs to be a reason, but it isn't given.'

[Vaern]

I'd generally assume that monsters don't break the world around them because there are things like Inevitables in the world whose sole purpose is to hunt down those who bend reality and defy the fundamental laws of nature. One of the reasons that becoming a lich should be considered dangerous business, for example, is that there is a type of Inevitable who specifically hunts down those who cheat death. Liches might be uncommon in a particular setting because those who might become one are afraid of attracting the unwanted attention of one of these.

[Ruethgar]

Its just like IRL, things part of the order of life don't try **** it up, only humans(players) do that.