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.