But what are the incentives for greater productivity within a given space of hours? At salaried positions, your point is more germane, because the benefits of efficient work to the worker are more straightforward: you finish what you need to do, you leave the office—and maybe you even receive a monetary bonus (in addition to this leisure bonus) for your efficiency.
But wage-work, at best, doesn't incentivize this sort of efficiency: if it's a job with fixed hours, irrespective of task-completion, then even highly efficient completion just means playing out the string until the whistle (say, by donking around on message-boards—a kind of limited or highly-circumscribed leisure). At worst, wage-work actually disincentivizes high efficiency: if tasks are fixed, but hours are dependent on how long it takes to complete those tasks, it's entirely logical for a worker to ensure that tasks require as much time as is reasonably possible to complete. (And that's not even touching on further carrots, like monetary bonuses for efficient work, which in my experience are not as common in the wage-earning world than in the salaried world—especially outside of commission-earning service-industry jobs, where the expectation of commission, or of tips, is sometimes figured into the wage-rate itself.)
I'm not saying you're entirely wrong, but I also don't think the compensation-structure in the US is adequately adjusted to render "more productivity = less hours" a fungible reality.
