Americans own cars because most of them live in single-family houses on large plots of land, and that doesn't make public transit for daily commuting a realistic possibility. In Paris car ownership is very low, maybe 1/3 of adults, but in rural France the car ownership rate is easily 95%+. I haven't seen a single developed area in the world that has violated the rule that low density = high car ownership and vice versa.
The other rule that I have never seen violated is that the large majority of middle and upper income people do not want to live near low income people, due to crime or other reasons. In Europe, poor people live in the suburbs, so the middle income live in the city with high density housing. In the US and some other places (south asia), low income people live near the business center, so the middle income live in low density housing in the suburbs. These are for historical reasons and cannot be easily changed.
The real reason Americans own cars is because we’re rich enough to afford a more expensive and more convenient system. Public Transit at scale is surprisingly cheap when compared to all the costs associated with car ownership * 10’s of thousands of people in even a fairly small community.
It’s really hard for someone who hasn’t lived it to really understand what it means to be able to walk to the shop. Then compare to when that’s not physically possible.
I lived within walking distance of my job and shopping for years near DC. To the point where I would go weeks without driving. But I didn’t sell my car and quickly went back to driving when it was even moderately less convenient.
Both public transport and cars can both serve low density suburban commuters as demonstration by many cities around the world. America doesn’t lack public transportation because of it’s size, population density, layout etc, it’s simply people choosing driving consistently in how they vote, where they move, and what they do when given the option.
NYC doesn’t have good public transportation because New Yorkers are different, they have it because it’s the only option that scales.