I asked this question more than a few times of my HR rep in 1 on 1 meetings to review my team's performance, when rumors were floating of another layoff (to meet the quarterly earnings commitments to Wall Street).
Every time I was told the same BS answer: "we don't want to lose our best employees to our competitors and even pay them to leave!"
What?!?! You mean you're worried our "best" might leave us and go work for the competition. How could that be if 3M was such a "great place to work" - you'd think would take less to stay at such a wonderful place.
As a mid 1980s hire and recent retiree, I can tell you HR was once full of good, well-meaning people who helped support people and their development. That all changed when the guy from GE came in and decided HR should be used to implement a despised and pernicious forced ranking system and then use it to "motivate" people to work harder and longer to be rated a 2 (below average) or 1 (unsatisfactory).
Such a frigging waste!