Sorry to take so long to reply Ted, I just found this now. On blue collar jobs, yes, Akron Ohio for example, began a program to welcome immigrants because local folks would not take manufacturing jobs. Other cities did the same but I found it hard to find RECENT info about this.

Your other question is really complex but in the old days when people got print newspapers you could draw maps and see where the New York Times boxes ended and the Boston Globe boxes began. Something like that is still possible if you look at the sports maps on the web based on Facebook followers where Yankee influence ends and Red Sox begins, or Giants vs. Patriots etc.