That cannot be true.
If you fire 15% of your team and the productivity stays about the same, you were wasting resources before. If some other guy was running a really lean team, and they have to fire 15%, they will be punished and you will get a raise.
And you would be strongly motivated to hire more useless people that could act as a buffer in case there's another layoff round.
I know, it's Meta, but they can't be that blind.