This would indeed explain why different cultures segregate themselves so often in cities, though I think that is starting to change now as the lower income regions get gentrified and the poor are forced out to the suburbs. After my absence of 30 years, I barely recognized Fells Point in Baltimore or the New York Ave. and Florida Ave. intersection in DC. Can't help but feel nostalgia when I see vacant streets of sterile bauhaus glass boxes replacing the gingerbreaded funkiness and bustling street character that existed in the old days. But then I'm old enough to remember street cars sparking all over DC...
Interesting to hear that B says Dallas & Austin and Chris D says San Diego follow the same south/east poor and north/west rich pattern. It does seem explainable for both those areas, with closeness to the Mexican border or greater distance from the ocean being less desirable locations for the elite to choose. I'd wondered if a reason for some of the east coast cities being this way could be because maybe as the original oldest sections of cities became more rundown, they were left for the lower classes to take as the rich moved westward where the land was emptier during the days of manifest destiny. But that wouldn't explain why the rich would move north.
Anyone know of any cities where the elite are in the south or east and the working class are in the north or west? Some cities must be arranged that way.
--tully