Are you suggesting car drivers move to smaller towns where it's actually economically efficient to use them? You wouldn't want car drivers imposing their noise, pollution, financial cost, infrastructure cost, and displacement on the millions of other people trying to live their life. It's very insightful of you to imply that cities should be designed for people, and not cars, so those millions can actually use the density to their advantage.

How about this? Let's move the population of Dallas Fort Worth to San Francisco, and vice versa, and see how quickly people's opinions about vehicle ownership change.

The main issue with having cars (or not) is that infrastructure that costs many orders of magnitude more than the cars has to be rebuilt if you want to switch between car-dependent and walk/bike-everywhere.

Yes absolutely, the only way for many people to live in one place is for them all to drive cars for all trips within that place. There are no other possible configurations.