The suburbs are inherently compatible with trains and really any public transportation. They were quite literally designed around the car and the expectation that everyone would have a car.
Unless you plan to bulldoze the suburbs and then force everyone to move into higher density areas your anti-car dreams are never going to happen.
Although there are many American cities that could get much more anti-car and public transport would work. LA could theoretically not be such a car city with the appropriate infrastructure built in.
Why are the anti-car people anti-self-driving car? With self-driving cars we could mostly eliminate private car ownership.