Another trend in America (not Detroit, where even housing in the suburbs is relatively cheap thanks to a declining regional economy) is for the old, inner ring suburbs to be going into decline, while portions of the inner cities gentrify (thereby driving the poor to the close-in suburbs). You see this phenomenon in DC, Boston, Chicago, Los Angeles and other cities.
Interesting remark.
Speaking of Europe again, I’d like to say most of our cities follow the same pattern.
A very large (and also very rich) European city like London might constitute somewhat of an exception though.