World-Building Turn-Offs

[Xuc Xac]

Except that isn't what happens. You pick up the shiny magical sword, and if it's shinier with magic than your existing one, you immediately start swinging that one.

That's the point that seems to be being missed. If the ancient high-tech civilization had guns and laptops and magic swords, then the current civilization doesn't need to find only pristine magic swords and rusted junk. There would also be Glocks +2 and Laptops of Wisdom in pristine condition too.

Anyone can do magic: how can civilization survive like that without descending into anarchy? It’s like if everyone had the potential to construct an atom bomb in their basement, someone somewhere would set one off.

"Anyone can do magic" doesn't mean "anyone can cast wish". A world where any first level commoner can cast magic missile once per day isn't as dangerous as a world where the first level commoners all have guns. Our world hasn't descended into anarchy and we live in a world where anyone could theoretically build an atom bomb in their basement. There was a 17 year old kid who made his own yellowcake uranium and built a nuclear reactor in his garage. Not everyone does it because it's really hard to do and you have to be smart and dedicated to pull off that high level engineering, but low-level stuff like making a lamp shaped like an elephant that lights up when you pull the trunk is within easy reach.

If they're all that durable, I will concede the point that modern-style guns would be usable if left behind by ancient civilizations. I still maintain that producing more of them without modern metallurgy, manufacturing processes, etc. would be impossible, and that without the background knowledge we have from historical guns and without examples of Renaissance guns to work with (as those would not be as durable as modern ones nor as intuitive as point-and-shoot), getting from point A of no guns to point B of gun tech that is widespread, understood, and good enough to rival magic is not guaranteed at all.

Guns would be usable if they were enchanted like the swords from that same civilization. If they are still usable, they can be reverse engineered fairly easily. Right now, at this very moment, knockoffs of AK-47s are being produced with Iron Age tools in workshops all over Africa and Central Asia. And why do they have to be good enough to rival magic? They have to be good enough to rival magic for wealthy adventurers to use them, but they only have to be better than a spear for the military to buy 10,000 of them.

Regarding the number of casters needed: if not destroyed, magic items last indefinitely. If you have just one wizard in one city making one flying carpet per year, after a hundred years that's a hundred flying carpets, plus however many are brought back by adventurers, plus however many the society had beforehand, and in the meantime he can spend the rest of his year making other beneficial items at a similar scale.

Well, when you put it like that, the Glocks+2 really are conspicuously absent.

You don't have a choice of just two machine guns; you're using the wands or machine guns as your army's primary weapon. Do you want something that requires training to use, to ensure that only a subset of the population can use and that that subset would be trained to use safely (the bows or wands) or something that anyone could pick up without having the discipline and training to use it well and safely (the crossbows or machine guns)?

History says "something that anyone could pick up". Most militaries didn't want to plan their wars 20 years in advance, so "two weeks to train a musket brigade" was deemed superior to "two decades to train longbowmen". The peasants might rebel but so what? They could have rebelled with bows too. Either way, they'll be fighting your loyalists who are similarly armed, so it's a wash.

Regarding startup costs: Sinking funding into developing nonmagical means of flight profits later. Enchanting more of the same known, reliable means of flight profits now. The Wrights' first functional airplane used bicycle parts they had on hand from their shop, an engine from a car manufacturer, and other things that required a technological society's existing infrastructure and economy of scale to bring down the cost to the level that two hobbyists could build it. Not every wizard would try to figure out and build all of that from scratch when he could just enchant something to fly for a fraction of the effort and cost.

Why would a wizard need to do all that from scratch when the Wright Brothers didn't? The wizard who makes an airplane would be doing it after previous generations of wizards had already set up that infrastructure. The wizard aviator would have the benefit of scavenging parts from earlier inventions too.

Once again: you cannot assume the same development path as real-world history. We developed gunpowder at least as far back as ancient China, where it was used for fireworks at first rather than weaponry, and the recipe is simple enough that you can stumble upon it by accident and refine it from there. In D&D, they have dancing lights and other means to make pretty lights in the sky, and you have to be a magic user to do anything alchemical.

You can't really say they wouldn't develop gunpowder for fireworks when they already have dancing lights, because they weren't looking for fireworks. They were looking for an immortality potion and mixing random things together based on symbolic properties rather than chemical properties. They stumbled across it like a thousand monkeys banging on a thousand typewriters and eventually producing "To be or not to be? That is the question!" at random. Gunpowder was discovered in the real world in the Middle Ages, but it didn't have to be. It didn't require any pre-existing infrastructure. It's just a mixture of three naturally occurring substances that can literally be picked up off the ground. It could have been discovered at any time before or after that if someone had just stumbled on the right mixture of stuff by chance.

A lot of world-changing things were discovered that way. Someone tries to make something, and it doesn't work, but they accidentally stumble across something else useful. Unfortunately, in most settings as they are written, research either works as intended or just fails.

And gunpowder isn't even necessary for a civilization to develop guns. They just need to have the concept of flinging stuff really hard. If they have the idea of the blowgun (or even the pea shooter), then someone could try to think of ways to make stronger guns to launch heavier and deadlier darts. Several countries experimented with using compressed air for rifles as a safer and more portable alternative to gunpowder (non-flammable and easier to resupply in the field), for example.