Don't you think that has anything to do with the massive number of illegal immigrants that arrived in the last 10 years?
I think it more likely that the wholesale off-shoring of what were formerly high-paying jobs is the predominate factor. Read 'The World is Flat' by Thomas Friedman.
I have read it, I'm just not completely in agreement with his analysis. Some of the reduced wages are the result of off-shoring, no question about that. Bu, remember when we were going to have the "giant sucking sound from Mexico" if NAFTA passed? That didn't work out very well, because the rule of law is not as strong south of the border (all the way to the Antarctic. Our companies tried that, but ended up bringing out neighbors here to work so their capital equipment investments would be protected. That is a problem in China as well, that our equipment isn't stolen outright, but duplicated and our customers stolen. It's only really been going gangbusters for 10-15 years, but it'll come around to bite them. Our current government legal structure encourages short-term gains over long term gains, so that's what companies are doing.