The working class in America is wealthier than 94% of the human race. I've always found it suspect to think of them as an unconflicted force for social change. From an international perspective, they have much to lose. The status quo, for them, is not good, but could be much worse.
I wish I still had a copy of Franz Fanon's book The Wretched of the Earth. Sartre wrote an introduction for that book in which he spoke to this issue, but I can't remember the words, it's been at least 10 years since I read it. I remember the idea was something like "What was the debate between capitalism and socialism in the West but an argument among theives over how to divide the spoils" but I don't remember the exact words.