I think they totally glossed over 'regulation'. This period of time correlates heavily with the rapid adoption of a wide range of industry imposing regulation. This diverse, but rapid, addition of regulations in every area, including labor, safety, pollution/environmental, and financial, has squeezed every industry, heavily reshaping those industries as well as how they use the labor workforce. I think the regulation may be largely to blame for driving a lot of automation. One thing that you might include in regulation, is poorly thought out ham-fisted legislation giving, the very important, but prone to corruption and excess, unions an overbearing cabal over the industry they oversee. Here in my state of Illinois, we are passing the dumbest union laws, allowing unions to violate state-laws and banning certain kind of employee contracts, while creating a system where state workers more or less blackmail taxpayers for their own pay-rates through their union and unions can gate-keep employers, determining blacklists for employees.