Not sure where you live, if you're in Chicago, the Suburbs or where .... but I've seen the suburban population of Poles, German's, Italians and Greeks EXPLODE due to their exiting the city. There is still a small portion of "German" and "Greek" pockets in the city that I used to be familiar with, but they're far smaller now than they were say 20 years ago. Same thing with Little Italy, most of it's just restaurants and funeral homes, the "old neighborhood" moved out but still maintain their businesses in the city.
That's why Obama is so desperate about the "Jobs Bill". He needs to maintain the solvency of a number of Dem enclaves. If they cease to have federal money to keep them afloat, Chicago, Detroit, NYC, and other places would be unable to support so many worthless Dem voters.
Visualize a Chicago which was no longer able to afford Welfare or large numbers of public employees, where the only way you could live there would be if you worked a private-sector job.