Life is a lot more than cities and traveling between them. The USA has a vast array of things not in it even close to cities. The USA is vast and beautiful and many people like to explore our nature, parks, etc, etc.
Realistically what's the proportion of car use between going to/from work (or the grocery store or other similar destinations) vs traveling the country for your average USAian? Especially one living in a dense metro area of some kind? And even then, I'm not saying we get rid of all cars, just that owning one shouldn't be a necessity in a massive, dense metropolitan area in order to get from point A to point B.
I own a car myself and use it regularly for longer road trips the few times of year I do that, but I avoid using my car like the plague if I'm traveling within 90% of the Netherlands.
