What will Los Angeles and other American cities look like in 20 years and what will happen to the suburbs?

Using my city as a reference (Santa Monica), homes will be torn down and replaced with apartments/condos. A landlord can make more money crowding people into one small area then having a single family live there. Then again, people who owned their homes here sold them to landowners who were going to do this. Cars will still be the dominant form of transportation for a while. If oil hits 200 a gallon, as predicted by goldman sachs, then you will probably see more lower income people take alternate forms of transportation.