As I tell my students, I've never actually had a job. On the other hand, I am also giving up 5-10X in total compensation.
One of my colleagues (and a close friend) resigned while I was the Chair, so I got to take that call. He was leaving to join one of the FAANG as the chief architect of their persistent storage tier. In having the "what could we do to keep you" conversation, I told him: "Look, I understand we are not talking about only money here, because we cannot compete on that dimension."
He never gave me the number, but described it as "baseball-player money". And as he was a Red Sox fan, he was not talking about the League minimum.
This of course gets back to when is enough enough. Another thing I tell my students: If you keep score with money, it is hard to be happy, because there is always more. To be clear I did not (and do not) begrudge his decision---he's a lot happier as a practicing engineer than he was as a faculty member. The fact that he is paid (much) more is a happy accident.