Manual labor also has its limitations. I used to work in construction, and after my 37 hours my body didn’t want to continue. Sure, I’ve worked more some weeks in an attempt to get roofing done before a period of bad weather, but I’m not convinced I actually did more work than regularly, because I’d just be more tired the following day/week.
Especially how can you be productive? I mean you’d dig more holes if you work more hours, but mental work just breaks down when people are overworked.
Manual labor also has its limitations. I used to work in construction, and after my 37 hours my body didn’t want to continue. Sure, I’ve worked more some weeks in an attempt to get roofing done before a period of bad weather, but I’m not convinced I actually did more work than regularly, because I’d just be more tired the following day/week.