"Learning new skills can help, a little. At Ingram Micro, temps trained to drive forklifts earn $10 an hour. " That's pretty much the way life works...anywhere. The more you know, the more you're worth.
I think the point of that quote was to show you how little even skilled warehouse workers can expect to make. The more I read about the proliferation of temps in the US the more depressed I become. I know someone who works as a "permanent temp." There is no end date to her assignment, and she works 40 hour weeks year-round, but she will never be hired as the company (an Ivy League university) doesn't want to be responsible for her benefits. She has a Master's degree and does highly skilled work for them, I can't imagine how tough it is for temps on the other end of the educational scale. It's an entire ecosystem of "disposable" workers.