I've never worked somewhere in which mentorship was formalized *and* something for which there was a clear relationship to promotion. Not saying that the only way to get me more into it is by paying me or threatening compensation, but when push comes to shove the things that aren't tied to promotions are the first to go (especially in management).

And also, I've noticed my desire to mentor has (slowly) gone down over time. I'm trying to avoid ageism and certainly not assume that seasoned COBOL devs are less eager to mentor than junior devs, and I hope I'm clear in that I'm projecting what is something of a personal limitation onto my future self.