Anyone know if there is a common source for the recurring predictions for reduced work week?

They keep coming back to increased productivity from technology, as if that alone will roll back work hours. Because if you get 8 hours work done in 4, why, you can just go home. Heck, if their workforce becomes 100x more productive, employers will just reduce hours 100x, keep salaries the same, keep production the same. Yep.

I don't know of any employer that doesn't want to simply pocket any productivity gain as profit, or us it as a competitive advantage.

Eugenics was in more than just Germany in the 1930s. Amazing how widespread eugenics ideas were (so widespread they came out in this high brow Brit's 'utopian' future).