I can't convince myself that would work. What if it isn't that people hit a peak of productivity at 20 hours of work per week, it's the minimum they try to do a

I can't convince myself that would work. What if it isn't that people hit a peak of productivity at 20 hours of work per week, it's the minimum they try to do and still be acceptable to their boss. This could happen if bosses just assume that people work close to 90-100% of the time during working hours. I am sure no one is honest about it. If 20 hours were the new weekly target instead of 40 it could negatively impact people if productivity declines on crucial things. That could happen if the new minimum acceptable amount of work to management were, say, 10 hours. So people would similarly spend 50% of their 20 hour working week avoiding work. So there could be a temporary shock throughout the economy as supply of things decreased until things adjusted.