>we find that people with less in-office time tend to have qualitatively worse performance. At least in my field, being in the office, spending time with your co-workers, and getting to know them has value.
I think you are confounded by the fact your most overeager overachievers are going to return to office no matter what.
I'm not persuaded that's the only thing going on here, but I'm sure that is part of it. Nonetheless, I think this is why many employers pushed for RTO.