Even in large cities in California, it really depends on how much time you want to or can afford to waste on public transit.

Specific cases do work - or at least work better than the car-owning alternatives, for example major transit directions for short-ish distances in San Francisco. If your life revolves around a few of these, you are doing pretty well without a car ... and you still can't escape from that area without one. A significant additional "sweet spot" zone is where car usage has been made - deliberately and assiduously - unbearable. The choice is then about a lesser aggravation, rather then desirable service. And so we get the quality of life we deserve, and that's not great.

Nobody is arguing that YOU should own a car. If you are happy without one that's great and carry on. But that's rather specific situation.