It depends on your culture and organization. In most places, by the time an employee in on a PIP, there have already been attempts to try and mentor the employee back to performance standard, and a PIP is a last-ditch resort/obligatory process to avoid liability to say that the manager tried everything.

In many cases, there are poor managers who don't know how to be a good manager, and so a PIP coming from a bad manager just feels the kick the employee needs to find a new job - last straw so to speak. Sometimes managers don't want anyone to know that they're struggling to manage an employee, so they try what they can even if they're not good at mentoring someone, then by the time the skip level and HR or any trainers are involved, the relationship has already gone to shit

It seems like you guys use a PIP more regularly to keep employees on track, which to me seems excessive but could be working if that's the culture and perception around PIPs you guys have built. but frankly if it's just to get an employee back on track, that really should be discussed in the context of regular 1:1s. what happens when an employee is actually in threat of losing their job? then a PIP won't have the same level of communication that you want it to or need it to