It depends on the tone of the setting. Someone who gets their leg broken in a Forgotten Realms game can usually find a small-time priest to cast Cure Wounds on them, preventing most disabilities that aren’t from birth. Someone who gets their leg broken in Warhammer Fantasy has to hope within their gimped traveling distance that there’s a priest of the correct faith capable of appeasing the gods for the healing to happen, before their detriments become permanent. As such, having a disabled character in a game with more accessible healthcare requires an extra degree of explanation, on top of the PCs’ and players’ emotional response to someone being so downtrodden. The circumstances of their ailment, who or what was responsible, how they see their ailment and work around it, all are weights on the players’ suspension of disbelief that a GM has to take into account that they generally otherwise wouldn’t with John Miller, the able-bodied dude who runs the mill with a wife, three kids, and a problem with rats stealing the grain that he mills. It’s like a Chekov’s Gun in that sort of way, the GM as a storyteller surely wouldn’t spend the effort to decide that an NPC has a trait that is notably separate from the default without it being somehow relevant to the plot. The mage asks the party to do a quest for their magical research, a general asks the party to do a quest for national security, and a person in a wheelchair… what desire do you give them that wouldn’t be misconstrued as able-ist or a waste of that character trait? It’s very difficult, often comes with an air of making some kind of a statement, either that they’re a writer capable enough to wear disabled-face without it being offensive, or taking a preachy high-ground telling people a message about human sympathy, determination, and adaptability that they’ve already been made well aware of by the existence of popular culture.