That’s not how this works. Let’s assume there is a correlation between productivity gain due to AI usage and outcome per working hour. No manager/CEO would say “hey, due to AI my workers get the same work done in 30h for which they needed 40h before - let’s cut their working hours down to 30h with same salary”.

No, that’s not happening. Shareholder value has to increase so keep working 40h and produce more outcome.

Productivity per capita has already 5Xed since the 40 hour workweek was implemented. The resources required to comfortably raise a family in a suburban home can be generated with only a few hundred hours of labor per year. Everything they had then is easier to produce now, and the things we've gained since like consumer electronics require barely any human labor at all to produce.