I mean yeah, they're disabilities in the sense that they're a condition one ends up with that challenges them in some way, but it's not something "wrong" with a way their body works, it's just a type of damage someone can receive. They're also arguably rather excessively easy to use as a stock disability from a storytelling perspective. Imagine if you were making a story and were compelled to give some characters some medical conditions to add to the depth of the story, and you thought "meh, we can just remove a bunch of their limbs". Or to put it another way, unless the person is a Cyanide and Happiness character, nobody is going to write a biography in their elderly years titled "My Life As A Guy With One Hand" so as much as someone might write one titled "Life As An ADHD Person".

I have the same semi-complaints (not really complaints per se) about Pokémon. There was one single blind character-of-the-day in the original season (because he was old), the manga version of Bryce was wheelchair-bound (kind of inevitable though for him), and the remake version of Wally was hinted to have asthma, but for two and a half decades of journeying around the world, there was never someone mainstream who popped up who had some kind of uniquely driven medical trait, which after so long doesn't make you complain but makes you wonder if they're avoiding it.