In my experience in high performing tech companies, I've seen about 40 PIPs. There are 'utter tech incompetence' PIPs in the world, but as far as I've seen, they are far less popular than 'thoroughly uninterested in working' PIPs, 'disliked by new manager' PIPs and 'person has a work unrelated crisis' PIPs. Those tech related PIPs will normally have all the symptoms already in the first review cycle. If someone made it to their 2nd year in the company, tech incompetence is not really the issue. It's just unfortunate that nobody provides stats for this kind of thing, so we don't have to just rely on "you have seen" vs "I have seen" arguments.