That isn't how comparisons work though. You can't compare a 20-hour/week company with good culture to a 40-hour/week company with toxic culture. You have two variables uncontrolled in that comparison.

Compare both companies at 40 or both at 20. The good-culture-40-hour would outperform the both the good-culture-20-hour and bad-culture-40-hour so why wouldn't all companies aim for 40/hours with a good culture?

It could be argued that it is impossible to have a good culture and 40 hours, but that needs a lot of analysis.