Yet you cannot deny that the level and wealth systems favor a selfish mindset, with numerous magic items to draw you into doing anything to get them, levels to grow stronger for your own benefit and so on, with no commentary on why a good character would seek these things out, and again only 2/11's of the classes actually interact with the alignment system in any meaningful way. what you list, are broad generalizations and don't comment on how the adventurers actually adventure. they provide very general moral guidelines, but they notedly keep away from actually examining or commenting on what this means for adventurers, the people your supposed to play. don't you find that a little odd? you'd think that after what, 40 years, DnD would have some section in the core specifically commenting on the morality of adventurers in relation to the alignment system and what ways they're recommended to be played out to advise people so it isn't misused- instead the alignment system has been downsized into being irrelevant, and the 5e DMG focuses on other things.

Which says how important alignment really is: not very. its a thing to concern people interested in the divine of DnD 3.5 and nothing more. DnD is driven by its content based nature, and if there is no core content discussing how Adventurers be moral or not be moral, then its not something DnD is normally worried about.