Why? Less money velocity would mean cheaper goods. And maybe less need for services if there’s more free time. Why pay for a massage if your wife or gf has time to give you one?
The “working norm” of 40+ hours per week is purely arbitrary.
And you still didn’t speak to misallocation. If the potential inventor of a controlled fusion reactor chooses to push money around in a Wall Street whorehouse instead, it’s a net loss for society and the Earth.