If magic exists to eliminate all disabilities, then there should be no smart, rich people with disabilities in your world
I disagree. I know plenty of smart people with disabilities who wouldn't take a cure if it was possible. Most of them are autistic. Autism is a disability in a world that doesn't accommodate it, but it doesn't have to be. It's a disability politically, not intrinsically. And deafness is pretty undeniably a disability, but I've read about deaf people not wanting to join in on hearing society because they think the deaf community is better.
This might sound hard for you to understand if you're fully abled, so I'll put it in terms you can understand. Imagine if tomorrow scientists invented a cheap, painless procedure to install a third arm in your chest. Everyone's getting them because they're so useful, and clothing stores are quickly switching to shirts with three arm holes. It's getting hard to find shirts with only two arm holes, in fact. Even if everyone you knew said they preferred having three arms, would you get one?