This is part of the problem I suppose. Top talent likes to get things done, will do it anywhere. There's always a group that gets nothing done, they're less visible when they WFH. But for the middle, how much productivity do they gain or lose by going remote? Also, the mix of "stars" is probably different on site or remote. Some people who really were crushed by commuting and working in a distracting office are shining at home, others who need that routine and comraderie are struggling to be as effective.
Voluntary office work probably helps, but friends of mine who liked being in the office talk about going to work to sit in an empty bullpen and do the same zoom/slack teamwork they'd do at home.
For me, I don't have the experience as I have a job that needs to be on site.