At root of your statement are the American oddities in how employment is conducted.
Aphrodite
2

Yeah a few years ago, I would have believed you. However, to0 much research says otherwise. Even the San Fran Fed rejects the notion that lower wages are from a decline in union membership. Unions in the south were formed for the purpose of keeping blacks out of the labor force…Newly freed slaves would have bid wages to low. You seem to be trying to tie in anti- union sentiment to racism, but truthfully Unions haven’t really been of much use to our economy sense the advent of the 40 hours work week. Again, it’s key to remember it’s the workers themselves rejecting unions, no one has made it illegal to join them. The common leftist response to this is that workers don’t know any better , but I don’t believe that at all. Unions just suck at recruitment and now that they can’t force membership or payments, people are freely disassociating.

Lower average wages are mostly a result of high income baby boomers retiring leaving younger less experienced workers to make up the composition and also the growth in labor from women entering the work force. Free trade has dramatically reduce poverty globally ( which is why economist have a rare consensus on the issue). In the last few decades more American classes moved up above middle class than fell out of it. The evil corporate greed narrative is a painfully basic explanation for a complex socio-economic issue.