Current hunter-gatherers populations that can be observed in the world nowadays "work" only 20 hours a week. So 40, or even 50 for some, is way out of what would be "natural". Of course we now live longer, etc. I'm just countering the argument that 40 h is little to survive.
I would have to agree with you. When agriculture was invented, so was "work", that is, something that is separate from your real life. There's a reason agriculture didn't properly take off for hundreds of years, even though people knew that planting stuff makes it grow. Tending the earth was a shitty business, hard work that took most of the day without proper tools. Gathering stuff was a lot easier.
Work is in no way "natural". Having to eat is quite natural but for most of humanity's history you could just eat stuff from your immediate surroundings, with little time spent on gathering food. These days we spend 10 hours a day to a acquire the means to eat. I'd say people we're a lot smarter thousands of years ago.
Yep, and that was mostly before some fool introduced agriculture, which led to 1000-fold increase in the human population... not to mention the introduction of diseases because we're not meant to digest agricultural products. Doh!
It's not even about agriculture. In medieval europe peasants had a lot of leisure. Of course harvest season was brutal, but much of the rest of the year was easy.
Asian rice agriculture was endless back breaking work. But that wasn't the case in Europe.