"The eight-hour day movement or 40-hour week movement, also known as the short-time movement, had its origins in the Industrial Revolution in Britain, where industrial production in large factories transformed working life. The use of child labour was common. The working day could range from 10 to 16 hours for six days a week."https://en.m.wikipedia.org/wiki/Eight-hour_day
So there have been precedents to reducing working hours (and days), although I think that there are at least two cultural "accelerants" that will work against that in this fourth industrial revolution.
1. Parkinson's Law: after my personal big wave of automation two years ago, in theory I should be working the equivalent of a four day week 😉 but in reality additional tasks (some meaningful, some... less so...) simply occupy the empty space.
2. The irresistible, pavlovian response to the always-on culture, enabled by technology but driven by our baser instincts.
In summary, I think the lesson is to educate ourselves and our kids to be as irreplaceable as possible, embrace such technology as labour saving miracles and to be brave enough to choose the more meaningful routes as often as we can.
PS I, for one, welcome our new, robotic overlords... 😎