What happened to the Keynesian 15 hour work week?

In 1930, John Maynard Keynes predicted that technological change and productivity improvements would lead to a 15 hour workweek.
He wondered what we would do with our time.
It turns out that he has been pretty close in terms of productivity growth. He predicted an 8 times increase in productivity, which, according to Benjamin Friedman, economist at Harvard, we are right on track to achieve.
In truth I think the metrics of output per capita that these economists use probably understates the productivity potential. Much, if not most, of 1930’s work can now be done with the touch of a button.
Yet we work more and harder and in many cases with the same lack of efficiency that we always have. The 1930’s work week was 47 hours. It is now around 40 on average – and many are working much longer weeks than that.
Why? What happened to the 15 hours?
There are some macro-economic reasons why as a whole we haven’t realized the 15 hour work week.
But I am more interested in individual businesses and business owners. 99% of the 28 million businesses in the US are small businesses, many of these exist because an MSP owner had a dream of living a fuller life, gaining freedom and doing things their way.
Yes most MSP owners end up working longer hours for less money. A survey by The Alternative Board suggested that 80% of MSP owners work more than forty hours a week.
So, there are big, societal reasons why we as a country don’t achieve the 15 hour workweek. But why can’t MSP owners, who tend to be better educated and more driven than average, create a business that delivers the lifestyle they explicitly set out to create?
The reason is Michael Gerber’s concept of the technician and the MSP owner. The technician does the work, the MSP owner creates a business to do the work. Technology has empowered technicians to start their own business, which is great, but has neglected the need to build the business.
So we end up with technology that doesn’t fit and businesses that are overly complex, insanely random and take not 15 hours but 60 hours. Whole businesses grind away working harder to grow and succeed than ever before.
There is a better way: a structured approach to the work. Create the business as an engine that runs and consistently produces money FOR you. That requires an MSP ownership mindset rather than a technician mindset.
This is a key part of creating a human-centric business.