I don't necessarily buy the arguments around real estate investment, but I think it's important to note that the office is a construct from before the popularity of the internet. A lot of the current crop of exec started their jobs before remote work was viable, so their mental model of how work is done might require an office because that's how they used to work.

It's entirely possible that the question of "labor productivity" has nothing to do with why exec wants us all back in the bullpen, where they can gleefully stare at us from inside their offices.