With rising productivity and stagnant wages over the past 30 years or so, where does the expanding supply of middle and low skilled workers come into play on this issue? Is mass collusion by business leaders to keep wages down involved?
Mass collusion of business leaders was not needed in this case because of changes in the labor market (falling demand for and rising supply of workers in the US) that allowed US employers to do what had never before been possible because of the chronic labor shortages of US development in the century before the 1970s (with the added phenomenon of significant labor unionization during the 1930s).
The point is that employers took advantage of changing labor market conditions to stop raising real wages since the 1970s even as productivity per labor hour kept rising (hence the profit explosion since the 1970s and the speculation, debt, and resulting global crisis since 2007). I try to drive home the point that during the century before the 1970s, the US enjoyed a stunning rise to global superpower status and unrivaled prosperity while real wages rose every decade. In equally stunning contrast, since the 1970s, as and because real wages stopped rising, we have had a long-term decline in the quality of jobs (falling benefits, rising insecurity, etc.), rising unemployment, a return to 19th century inequality of income and wealth distribution in the United States, and finally a global capitalist collapse whose ramifications include the new Governor of California cutting over $1 billion from California higher education system that will damage the quality of your education.
The last thirty years of US capitalism have boosted profits and undermined the cohesion and prospects for the entire society. It would have been far better to respond to economic developments around the world in other ways than ending rising wages when productivity rose, but that would have required a system other than capitalism. And that is the issue we ought to be debating in this country.