The underlying requirement for a city to have good public transportation is to have more dense populations, which is almost always only found in older parts of cities. All the newer parts of any city in the previous decades were zoned to be less dense, so you're not going to see comprehensive public transportation any of the cities that have experienced recent growth. It's simply untenable under a certain amount of density, not to mention that most people prefer cars if they have the option to use them.