How do you know its the workers fault and not the nature of this role in the company?

I can't speak for EM roles, but ICs have many peers in similar roles to compare them to.

Also, there is an unofficial "pre-pip" phase, where the EM tries to correct these issues. Pips are the nuclear option that cost the EM a lot of time with almost no career benefits.

In reality it doesn't matter. Most of the time I'd wager it is not the worker's fault. But that doesn't materially change the situation.

From the perspective of the company, the company is almost never at fault.

As a manager it's your job to discern that, right?

They need to leave after the second PIP, having passed 2 PIPs the manager bears a lot of scrutiny "are you sure they won't regress again? It has been a year and you can't make a decision"

That said I've seen in sales a person only deliver above average when on PIP, passed the PIP and immediately mentally check out then PIP again and deliver. It was pretty maddening for his boss, the person was obviously skilled/capable but just needed PIP to be motivated to actually work