So clearly affordances to assist the disabled are going to benefit everyone ... eventually.
MS also had a very interesting design for disability brochure that talked about how even a "regular" person can be temporarily disabled - eg if you're holding a heavy bag of groceries, opening a door that needs 2 hands is very difficult. Designing for amputees will also help the 99% of the population doing grocery runs.
You’re designing for the interface/usage pattern, not so much a specific disability. A curb cut is a usage pattern for anything with wheels. A greyscale mode is a usage pattern for anyone that wants/needs information conveyed without relying on colour distinctions.
Tons of those adaptions are just plain useful in cases outside disability.
https://en.wikipedia.org/wiki/Tactile_paving
Anecdotally, I've observed that elderly people with grocery carts and people in wheel chairs have difficulty at cross walks navigating these features. The wiki mentions these points:
"...more thought should have been put into balancing the needs of vision-impaired pedestrians and mobility-impaired pedestrians, such as wheelchair and cane users, who can trip on the bumps."
While sloped, level curb cuts at intersections have been implemented primarily for accessibility legislation compliance, it turns out they are useful not only for the disabled but for people with strollers, heavy bags, etc. A similar effect can also be seen with the modern ubiquity of closed captioning.