I think you have never left your basement and went to the US?
Rudi is objectively not in a bad job situation. As an outsider, I see it this way: he is at a department better than any in Germany (not Zurich), at a university with so many more means than any in Germany and probably paid at least double the salary he would be making max in Germany. I don’t understand why we would go back if that’s what he really intends.
What exactly are you debating? The department part, the university part, the salary part?