Owen Hartherley of The Guardian argues that the belief the 21st century would be an era mechanisation would lead to shorter working hours has, in a way, happened. The only catch is that it has left the majority of us unemployed rather than free -- or working way too many hours to make ends meet.
[...] the utopian vision of the elimination of industrial labour has in many ways come to pass. Over the past decade Sheffield steelworks produced more steel than ever before, with a tiny fraction of their former workforce; and the container ports of Avonmouth, Tilbury, Teesport and Southampton got rid of most of the dockers, but not the tonnage.
The result was not that dockers or steelworkers were free to, as Marx once put it, "hunt in the morning, fish in the afternoon and criticise after dinner". Instead, they were subjected to shame, poverty, and the endless worry over finding another job, which, if it arrived, might be insecure, poorly paid, un-unionised work in the service industry. In the current era of casualisation, that's practically the norm, so the idea of skilled, secure labour and pride in work doesn't seem quite so awful. Nonetheless, the workers' movement was once dedicated to the eventual abolition of all menial, tedious, grinding work. We have the machines to make that a reality today – but none of the will.