When I was younger I was shocked to learn that during an LR companies would “over” cut in order to fund retention for critical people. You’re laying off 7%? This is a good time to free up some additional opex, so just add a few heads above target in order to free opex to comp important people. You won’t get that 7% back but overage you do, usually.
These companies could take a more twitter like "print out your code" or global stack ranking to lay people off but i don't think it dodge the problem people describe. The "A Player" could still be mad that all their coworkers got fired and/or the "pointless project" they enjoyed working on got axed and still leave. You just get the add cost, drama, and blow-back (see twitter) that a performance based firing would entail and probably open yourself up to lawsuits (IANAL) if you don't have an adequate paper trail for those performance based filings.
It is not that rare for critical employees to get grants as part of the layoff execution in a pre-emotive action, and now that I’m older I will note that I’ve been on the planning side of layoffs and this is fairly commonplace.