He stayed because he wanted to stay. He'll leave as soon as he feels himself too old for the job, which is what I'm arguing in this post is likely to happen during his next term. The technicalities about how he keeps himself in position or gets himself out of it, are irrelevant. That's the short version of what I would've bothered to explain in more extensive terms, had I not been as jaded by your being all over the place as I am right now.