My point is that fostering a culture of mistrust and competitiveness among the employees is antithetical to protecting social capital.
I won't effectively collaborate with you if it helps you being the low performer that will be laid off instead of me.
And curiously enough, I normally don't care about being PIP'd or layoff, as I engage in healthy job hopping so that I was never actually laid off over my relatively long career. Typically I'm one to see the early signs of trouble ahead and line up a new job in the next month or so.
But it wouldn't surprise me if it was found out that the culture of PIP and Stack Ranking helped to select for the ones that are best at navigating the corporate culture in the way I described above.
Well, when you get down to it, if you find yourself back-stabbing a coworker to keep yourself out of the bottom 10% during a RIF, that's not a huge badge of honor either.
A layoff is going to sever some of those connections in the short term, but the number and quality of connections isn't a function of how people feel about their job. Stack ranking and PIPs are tools that the company uses to mitigate the impact of letting people go. In other words, they're there to protect social capital (for the good of the company, don't get me wrong) versus doing something like picking a random 20% of people to eliminate.