How do we end up equating hours with productivity? In the industrial age, time spent putting cogs onto shafts was roughly equivalent to widgets produced. Management ends up, approximately, with a knob to turn: add more hours and you'll get more widgets. This conveniently ignores all the nonlinearities like diminishing returns and boredom and unintended consequences, but it seems to work, more or less, and it's simple. So, very attractive.
Even more compelling is the observation that productivity takes time. It's very hard to argue against the idea that all productivity takes some time; even flashes of insight require you to lay the groundwork, sometimes for years, by studying the problem.
Here we have a cognitive bias at work: we are assuming that correlation implies causation. Work takes time, therefore if we add more time, we'll get more work out.
It even sounds fundamentally wrong to say: "Putting in more time will not produce more value."
And we need some kind of payment unit, which might be the stickiest part of the analysis.
How then, with all these ideas embedded starting from childhood, can we possibly create a work environment where you don't have to think about how many hours you're putting in? We'll have to fundamentally change the culture and metrics we use. The resulting organization will probably look very different from time-bartering organizations.
I would find an organization like this to be very compelling. A place I might want to work. A place I might have to create just so I can work there.
I already have created such a place; it's my home office. Unfortunately, no one but me can work there with that environment. I'd like to figure out how to do this when other people are on the team.