Earlier quoted context omitted.
Can be done too. I live in a rather big city, so I don't own a car, as I can perfectly go by using public transport.
Only if you limit your work and social life to that particular city. Not something most people want to do.
Won't work everywhere, e.g. from what I saw when visiting I don't foresee US cities rapidly integrating enough good public transport to properly replace cars within themselves, and from what I've heard about how municipal organisation works in the US even less so for a convenient and well integrated intercity network, but it can be done.