It feels like the big elephant in the room about shorter work weeks and more remote work is that lower level employee productivity is not the issue with them (likely at all).

And it isn't even that managers and higher-ups have some biases against such schemes (which they certainly do).

It's that such schemes put a clearer focus on the actual role managers and higher-ups are supposed to be performing, namely organising employees and their tasks and priorities into coherent and well-planned projects. Managers are, on average, not actually good at this. And the problem is systemic ... the average work culture doesn't have a good sense of what this looks like. Instead, there are "glue people" all over the place, working beyond their roles to fill in the gaps and keep things together.

But, with a less "monolithic", co-located and co-active workforce, the need for actual coordination beyond "do the things! LFG!!" becomes very real, and very anxious for people who either don't know how to do that or don't want the world to find out that things were actually working fine in spite of their inability to do it. A remote and discretely scheduled workforce necessarily asks accountability questions like "who is responsible for planning this?" and "this isn't my responsibility, you need to get someone else to do it" etc.

Managers and higher-ups aren't comfortable with their actual value being scrutinised more closely. And in many ways, it's actually understandable ... as they likely don't know the answer themselves.