For me it seems like the 40 hr work week was constructed not for productivity but as the max amount of workable time where a worker would feel like they still h

For me it seems like the 40 hr work week was constructed not for productivity but as the max amount of workable time where a worker would feel like they still have some sort of life outside of work (weekend + 2-3 hrs a weekday of free time). Even then you can be constantly exhausted. Anything higher and you basically accept you have no life.