Here's an article which argues that wages have not been growing in line with productivity since 1973 because, since then, workers have been compensated with fringe benefits of increasing value, in lieu of greater wages.

[http://www.heritage.org/jobs-and-labor/report/productivity-a...]

I'm sure that this is not the whole story, but I bet it's a big part of it.

Financialization of the economy. The fall of Bretton-Woods. The fall of the gold standard. The repeal of Glass-Steagall.

Could it be an oversupply of labor that was caused by the availability of the pill and the following growing immigration asking for lower wages instead of incumbents https://tradingeconomics.com/united-states/labor-force-parti...