I appreciate your words so much ❤️ you're absolutely right.
Regarding the first part, in England that's called a "protected conversation" which pretty much is what my manager had on Thursday. The person being disciplined sees everyone else as the ones to blame for his lack of leadership and has a strong victim-mentality, so wouldn't just quit. But my manager wanted to get him to quit rather than fire him as if he was fired it was for gross misconduct which means direct dismissal, and he didn't want to leave him without a job overnight - even if there are several reasons for it. Ultimately he was not fired but last minute got issued a final written warning instead, and gave him the chance to still resign, but made it clear the smallest misconduct would get him fired without notice.
Regarding the second part, it's 100% correct. This person, unfortunately, needs to leave. He's been given multiple chances in his journey and there has never been sustained improvement regardless of the support he has received. He's thrown his whole team under the bus instead of taking the slightest accountability for the issues, when he is the head chef.