Comment by Qem

> I mean, a combination of political and economic factors from 1930s to 1960s forced the wealthy to return a portion of the returns of automation to the remaining working people.

The credible threat of communist revolutions put the fear of god into the capitalist elites. So they had to share a larger share of wealth with workers, beyond mere subsistence wages, to keep them peaceful. With the downfall of USSR, communist revolutions stopped being a credible threat, and elites clawed back productivity gains, pushing workers toward subsistence wages again.