It's funny because in this response you are arguing exactly the same thing as I was in my first comment: team sizes are always defined by political reasons (at manager's level, I didn't mention that above because I thought that was obvious, but here we are).
The duds who are the best at telling stories about how important their project is are the ones who can get the budget their team growing, and they are also the ones who are the most likely to defend their interests in the event of a layoff. Because, as you noted yourself, it is never about every individual manager selecting their lowest performers and laying them off, and much more about individual managers (at all levels) defending their own perimeter.
And in practice, being good at this type of games isn't a good proxy for knowing which managers are good at fostering an efficient team under them.
The point I am making is it does not matter if you are cutting 3%. Sure you might end up taking out a third of the bottom 0-10% instead of 0-3% but what difference does it make? It won't be a material political concern for your 50+ percentile employee base.
It does, however, make a difference on the promotion side.
> Sure you might end up taking out a third of the bottom 0-10% instead of 0-3% but what difference does it make?
That's not how it works! You'd have entire projects or department being sacked, with many otherwise very competent people being laid off, and projects deemed strategic being completely immune from layoff.
And even inside departments or projects, the people best seen by management will be safe, and the people more focused on actual work will be more at risk.
The harsh truth is that an organization simply has no way to even know who the “bottom 10% performance-wise” are. (And management assessment tend to correlate negatively with actual performance)
The duds who are the best at telling stories about how important their project is are the ones who can get the budget their team growing, and they are also the ones who are the most likely to defend their interests in the event of a layoff. Because, as you noted yourself, it is never about every individual manager selecting their lowest performers and laying them off, and much more about individual managers (at all levels) defending their own perimeter.
And in practice, being good at this type of games isn't a good proxy for knowing which managers are good at fostering an efficient team under them.