Disabilities are not binary; it's not perfect health VS quadriplegic.

For some people, it's just harder to do everyday things. It doesn't mean they can't move around. And for people getting older or with a degenerative disease, continuing to do things normally is also a matter of pride.

To put it in obvious terms, it's like saying that we can add 3-4 stairs at the main entrance, because anybody who don't like stair can enter via the damp alleyway in the back, besides the dumpsters.