I've never seen anyone put on a PIP where the intention was anything other than eventual firing. In all these cases, the person was doing an awful job for over a year, or in some cases, since they were hired.

Sure, but in our company, it's different. We ended up keeping the person in one or two of those cases (I forget the numbers because there were so few).

Why would the company hire them then? That just sounds like emotional abuse.