Economists (Keynes and others) in at the beginning of the 20th century projected that based on increasing productivity we would only be working about 15h a week by now. They actually did predict that this could become a significant problem, because many people need work for their personal fulfillment.
Now the productivity gains actually did happen, however what the economists didn't predict is that all the gains went to only benefit very few (essentially the holders of capital) and inequality would increase significantly preventing most people to reduce their work hours even if they wanted.