The autonomy of the different components of the city can be seen as a possibility for each of them to be even more different, thus for the diversity to increase inside the city. Yet, this diversity also means inequality, since the different areas of the city do not have to live together any more.
It's logical that, as cities become uninhabitable territories, their components withdraw completely from their urban context.
Cities are relics from the past, dinosaurs inadapted to human life. Lighter and more flexible environments will replace them (after a long ice age ?).