Central Planning v. Innovation
When you look at the time use studies which have been done in all of the "western" countries over the past few decades you see that the huge growth in leisure hours has come from the equally huge reduction in household production hours that these seemingly trivial domestic technologies have allowed. And of course, trivial domestic technologies are not things which are going to be thought about by a small group of men trying to run a 140 million people economy centrally. It's absurd but true that the workers' paradise simply ended up insisting that the workers were going to have to work much harder than us. For the system couldn't conceive of the real human desire, which is to labour less.