There's no reason you can't have frequent and convenient public transit as a subsidized service. This also ignores how between the years of 1938 and 1950 National City Lines — with investment from GM, Firestone Tire, Standard Oil of California (through a subsidiary), Federal Engineering, Phillips Petroleum, and Mack Trucks — acquired and dismantled the streetcar rail transit systems of 25 cities, including Los Angeles. We have worse transit systems in the US today than we did a century ago. All in the service of cars which we rebuilt our cities around.
While we fucked around for a decade the CPC built out a high speed rail network on the mainland. Similar landmass, similar geographical challenges, less wealthy nation. Guess Americans will have to wait until public transit is more profitable than making everyone get their own car with its very own JARVIS.