You could literally ask your taxi driver for their thoughts and it would be as helpful.
I prefer to see what the outcomes are from real-world experiments which to date are showing that shorter work weeks can be effective in many situations.
At some point he crashes but it’s not at 40hrs.
Is there variance in how long people can work without degraded performance? Of course. But it still degrades for most people.
...in software engineering. But then he steers into talk about menial jobs. I worked minimum wage jobs for over a decade before I got an app published. I rather doubt Carmack worked a manual job for very long but perhaps someone can correct me.
And I know he is not making a scientific claim because he is not done any research or has any background in this field. So his opinion does have weight. The same weight as literally any other random person on this planet.