I don't know about that. Companies generally do regular performance reviews, so there should be a lot of information about who the underperforming or merely adequate workers in each group are.
Objectively evaluating performance of somebody who is smarter than you is incredibly hard, and sliding into using "s/he is a nice person" metric instead, is an easy way to avoid that hard work.
It's probably one of the more rigorous systems in the tech industry that at least avoids this kind of bias, though there are certainly ways it can be gamed.
More than likely Facebook (sorry, Meta) will probably do it by team and trim underperforming departments. A low performer in an important department is probably more likely to stick around than a high performer in a money pit.