Earlier quoted context omitted.
It would be decently hard to find an argument against the 4 day workweek that would not ALSO apply to the 5 day workweek (compared to 6) - perhaps the only real one is "it's what everyone does".
But then why work 4 day/week and not 3, when 4 days/week becomes the new normal that burns people out? And then why not work 2 days instead of 3? And so on. How do we decide which model is the sustainable one?
Solving super hard Sudoku puzzles 40 hours a week will take a toll on your brain that solving super hard Sudoku puzzles 1 hour a week empirically cannot.
>How do we decide which model is the sustainable one?
Through the exact science you say you "don't buy" because you seem to believe companies operating in a flawed market are better at finding ground truth than literal science.