In fact, if we generously estimate that 10 million people live in high density metro areas that don't rely on cars we are looking at less than 3% of the US population. I think that is something to sneeze at.
I know it's hard for you to believe, but some people like living in high density areas.
SF only has a population of one million.
Basically the US has NYC and parts of Chicago as emblems of urban density.
De-urbanization was spurred by housing shortages post-WW2 and federal policy seeking to stabilize the housing market. The FHA was created to insure home loans that met a long list of requirements[1], which had biases towards increasing consumption (including cars) and racial segregation. The marketing and growth of suburbia was then promoted by various business interests that would benefit from that increased consumption[2]. The new suburban lifestyle led to the rise of modern conservatism[3]. Most (~85% [3]) of the US lives in metropolitan areas, so rural lifestyles are not typical and it would be vastly less efficient if everyone lived there rather than in cities.
1: https://marketurbanism.com/2017/09/12/financing-suburbia-how...
2: https://www.washingtonpost.com/news/made-by-history/wp/2017/...
3: http://americanhistory.oxfordre.com/view/10.1093/acrefore/97...
For example, LA used to have a great train network for public transportation until the automobile industry made sure to tear it down so people would be forced to drive cars.
In SF/BayArea people want zoning to change so there can be more housing/apartment buildings. Who's blocking that from happening? Homeowners who think that would devalue their properties.
Also, doesn't seem like people in NYC value cars or yards that much (at least not over living in NYC).