I'm sympathetic to your reasoning, and I actually think your conclusion about how people wfh is probably true (a minority finding it wildly more productive) but the problem I see is that most execs don't understand what a lot of their employees do on a day to day basis, nor do I think they could properly understand the data even if they had it as a result. And, if they did have it, why don't they show it if the conclusions are so self evident?

In reality I think it's much simpler: the work that executives (and some upper level managers) do relies on a certain amount of theater. They need to be seen (in person) and they to be seen doing work (in person). That's part of the "deal" with being an exec --- you need to be able to act the part. Then, they just assume that's how it should or needs to be for everyone else.