I'm a manager at Google and have therefore been privy to a bunch of PIPs. I know a bunch of people who have survived them and many of them have later gone on and had successful promos. I've seen exactly one case where everybody involved was resigned to the fact that the PIP would almost certainly fail and that is because the person being fired was a raging asshole. A manager who wrote a PIP designed to be impossible would themselves be given shit performance reviews.