A lot of people can't safely own and operate a car, either, whether due to poverty, age, or disability. While no transportation mode is the best for everyone, a diversity of options makes it likelier that each person will have at least one they can use.
(also, the "families need cars" thing is an artifact of American city design, not a universal rule. Tens of millions of families live in New York, London, Paris and Tokyo, and the majority do not have cars.)
Yeah, but those cities already exist, it’s not like American families can say “Honey, you know this is just an artifact of how our cities we’re designed, I’m selling the minivan!” Even if people would support a massive national infrastructure project to redesign cities and suburbs without the car in mind (and evidence is a majority won’t support that), it would still be the work of decades.
For now American families really do need cars. As for places like London, I have some experience here and the underground is a mess, busses and bus replacement services abound (and are terrible). https://www.bbc.com/news/uk-england-london-44953440 That’s no joke, I’ve been close to fainting myself and it wasn’t even a hot day. Our politicians don’t care about us, and we’re basically unable to get and use a car unless we’re minted and willing to sit in traffic. If you want to hold us up as a model, learn about the downsides you get trapped with when you give up personal mobility. A lot of us would kill for a car to be practical in and around London, and envy Americans giant cars and roads.
(also, the "families need cars" thing is an artifact of American city design, not a universal rule. Tens of millions of families live in New York, London, Paris and Tokyo, and the majority do not have cars.)