Is everyone supposed to live walking distance to their hospital/medical centers?

If the answer is no, why take up valuable urban real estate for hospitals in the first place? Why not stick them on country back roads? Transit can get the people there. If you have transit, it is not clear what you need cities for.

Thing is, Canada used to have transit lines between every little nook and cranny when the vast majority of the population lived in rural areas. Exactly what is being asked for. We eventually ripped it up because Canadians indicated that they didn't want to live rurally, they wanted to live in urban centres where they can walk everywhere, negating the need for those transit systems.

But now they want to go back. What's brought on this desire to live rurally again?

Are people expected to abandon their families when they move across town/to a different city?

Sure, I guess. I expect you will find that they do. Jetting off to lunch with your friend who moved to Tokyo will never be practical, save some fundamental shift in how we understand space-time.

Are people with disabilities that make walking/active transport difficult just expected to not go anywhere?

Why can't they use the tools that they already use to get around? If they don't even have that, transit isn't going to help. Transit will never stop in their bedroom.