Nah, that's often how it works - sure, becoming a rector would mean a pay increase, but it would require you to become an administrator and stop doing what you

Nah, that's often how it works - sure, becoming a rector would mean a pay increase, but it would require you to become an administrator and stop doing what you love, most likely permanently (as the gap of being away from your field of research for multiple years makes it hard to become productive again - returning to active science is definitely possible, but rarely happens), switching your career for an entirely different one as far as day-to-day tasks go. And if you're already somewhat comfortable as a professor, why would you do that to yourself? I've literally seen faculty 'drawing straws' as of who'll agree to be the sole candidate for a particular elected administrative position, because it's clear that one of them has to do it for the university to function, but no one wanted to.