Wouldn't it be nice...
Mostly is quite a stretch. It cost them a massive amount only offset by unemployment which is really difficult to correlate directly. Although it sounds great in practice, I don't think this is productive whatsoever. If the world was run this way progress would halt to a grind.
The only downside: The schedule was a bit pricey.
The only downside...
Sweden tested out a 6-hour workday — and it mostly worked
Still, in another life perhaps... wouldn't it be nice?