I would say it depends, if employee was set to be fired - there is nothing that they could do to avoid it, decision was made to downsize team, or they were assh

I would say it depends, if employee was set to be fired - there is nothing that they could do to avoid it, decision was made to downsize team, or they were assholes, had personal clashes with leaders etc. There are probably cases where pip is used to give a good person who is slipping a kick. That was probably initiated by their manager to motivate them back on track. However, a good manager would have a serious talk with that employee, rather than use formal HR process. So thats why (I think) pip is mostly used to get rid of people.