I know everyone wants to judge productivity instead of hours per week. But, I feel that 40 hours per week is a reasonable amount to request and that MOST (not all) employees are better managed by an hour standard instead of a productivity standard (which is hard to measure anyways). All of my employees work from home and at first I was all about judging by productivity, but then I realized it was being abused for the most part and that if I set rules for timings and hours worked, it would be simpler and easier, at least for now.
24 (3x8 or 4x6) should be what we shoot for as the new norm for ordinary employment. That's the tipping point where selling your time to someone else isn't necessarily the main thing you do with your life, even if you're "fully employed" through ordinary retirement age.
40 is WAY too much. I was last on 3 days a week and had an acceptable amount of time to pursue other interests when not working. Spending so much time on one thing is not healthy. It's better to have more time for family, creativity, outdoors time, etc. This will be the future norm.