At one point, Google actually was different about handling PIPs.
Back in the 2010s, I'd say that of the people who got PIPed, about 50% made it.
I'm sure such a statement will rankle feathers on this board, as it goes against the usual dogma that a PIP was, is, and forever will be always part of a plan for firing someone. But regardless, that's a fact. If you want to yell "YOU ARE WRONG" or otherwise lash out for stating a fact, log off this board and go get therapy.
And the people PIPed back then didn't languish either, At least one is a director now.
Just this month? Of the several PIPs I know about, 0% made it. All of them were shown the door. Now that's in line with the usual dogma around here, but I reiterate that it is a distinct change.
As near as I can tell, here's the new process: You get offered a PIP or the new standard severance (14 weeks plus one week each additional year). It is an either-or choice. If you are 40 or older then you have 3 weeks to decide per the OWBPA. If you are under 40 then Google could give you 3 seconds to decide, but from what I have been hearing Google isn't that awful (yet?).
Googlers aged 40 or older should not waste time when offered a PIP or the severance. You should do the math (hopefully they will actually tell you the dollar amount of your severance). Consider COBRA expenses and the like to keep health insurance.
Googlers under age 40 should probably plan ahead to be able to quickly answer the question.
One open question is I don't know if you are offered a fully-developed PIP at the time you are offered the choice, or if you are offered a mystery box (the detailed PIP to be revealed after you make the choice). If someone here actually knows (and not just speculate, but knows), please reply.