A lot of things managers and higher ups don't see is the human connection. You can look at the metrics, organize people by stack ranking and then fire the quot

A lot of things managers and higher ups don't see is the human connection. You can look at the metrics, organize people by stack ranking and then fire the quote unquote worst performers, but those worst performers can also be core to the business in other ways by being good team players or good to work with. That's when you get Jim the all-star programmer leaving because John the slightly underperforming guy gets laid off and he no longer has anyone with relevant interests to talk to. That's assuming that John is underperforming as a whole and not just underperforming relative to his team, which his team could be generally high performance. So then instead of a 150% programmer and a 90% programmer, you end up replacing both of them with 110% programmers for a net loss in productivity.