What changed was computers. Computers didn't just improve productivity incrementally. It was easy for the management class to deal with giving a worker an 8%

What changed was computers. Computers didn't just improve productivity incrementally. It was easy for the management class to deal with giving a worker an 8% annual raise when their productivity grew by 10%. Then computers showed up. And workers using computers were suddenly gaining 80% or 150% productivity (if measured with the same metrics as previously). The management class could not tolerate giving out wage increases that large. The 'work hard, be more productive, and you will make more' mantra was only ever meant to be a means to preserve the status quo. It was not meant to facilitate the large-scale social change that rewarding profound productivity increases with profound wage increases would create. There was a very well-defined concept, held by both the upper class and the middle and lower classes, that it should require 40 hours of sacrifice per week for 40+ years before a person could financially survive retirement. If people could retire at 40 years of age, it would throw everything out of whack. Or at least that was the presumption. All those stories about how automation and technology would enable people to work less have two sides. They're very appealing with workers. They're grim horror stories for those who define themselves by how many people they control and how much value they get those people to produce for a low price.