I think it depends on, as you suggested, the location one lives. I think it is safe to say that if one has a family and live in the North America, there are few places, if there is any, that you can live a comfortable life without cars.

I live in a city with advanced public transit system (of course, comparing to other NA apparently, not other continents). Theoretically, I can go around without much driving. But there are always moments that driving a car helps a lot. One example is going to Costco. A second example is to lay one's feet 50+ kms away from home. A third one is to go to a clinic whenever I would like.

Cars enable flexibility. I think it's pretty hard to convince people to drop it, UNLESS the culture completely changes. Culture change would bring economical and political changes as well -- but that's a multi-decade process. This is why, may I say, that a car free policy is practically impossible for most, if not every NA city.