There are some places in the US--probably Manhattan most obviously--where there's a culture that doesn't have the expectation that you have a car. But, while people living in most other cities can basically do a post-university lifestyle without one even in cities with relatively good public transit, a lot of their friends probably live outside the city, a lot of activities depend on cars, etc.

I do know an adult couple in SF who gave up their cars but I'd observe that they rely on Ubers and various rentals a lot. I don't think I know anyone in the Boston/Cambridge area who doesn't have a car. Of course, they exist but I don't know one.