Your city is very spread out because everyone has a car. This is why this is such a difficult problem - transport networks, whether road or rail - are a fundamental part of the anatomy of a city. You can't simply take a city which grew up around driving and replace that with taking the train, any more that you can transplant a crab's exoskeleton into a rabbit.

Nonetheless, our cities must eventually become crabs. So we need to have a plan for how we're going to make that transformation gradually, as the cities grow and evolve.