I can absolutely see magic not being able to correct genetic or congenital conditions. It can make sense for developmental delays aswell. But something like missing a limb from a traumatic injurie or blindness due to macular degeneration... There is no reason a mid level adventurer or powerfull character would not just use magic to heal or fix it.
Maybe an injurie by a powerful lich, or since kinda of cursed weapon that makes it impossible to fully heal with anything short of a wish spell...
Poor people on the other hand, should absolutely have debilitating injuries and disabilities that will never be fully fixed due to magic being expensive.
Funny thing is, some places love when people Dont have social media. I have had to go thrugh a lot of background checks for my jobs before and most of the time they are happy to hear that there is no social media for me to say dumb stuff on online.