I thought you were gonna make some cool points about world building but then the ending came. To address your DnD example; that’s already covered by canon. Adventurers and what they earn (monetarily, influence, and good old finders keeper’s wise) is at minimum a whole order of magnitude above what the level 0s that make up the world’s backdrop have access to.
A blind adventurer who is destitute could find a scroll of lesser restoration (not arguing it would work here or not, that’s DM fiat) or otherwise get access to restoration of some sort if sought.
The blind after mining accident level 0 beggar is screwed, but the blinded by hunting accident noble could see by the end of the day.
The blind from birth halfling who can not miss what they’ve never had before and who gets around just fine with blind sight, wouldn’t necessarily feel that there is anything to be fixed; use that wish people for legendary loot.
That’s the bleakest and reality is stranger than fiction angle tho.
They’re fictional worlds, it’s perfectly okay to make one in which differently abled people can feel represented without reality being a dick to them if you know, not being a dick is something that matters to you.