What typically incentivizes a professor to change jobs to a lower ranking university?
The most important reasons I can think of are private reasons. People do not live to work, but work to live.

What good does a job at a highly ranked university do, if your family/your friends can not live there or are unhappy to live there?
What good does a job at a highly ranked university do, if it is in a place you find boring or don’t like?

I would suggest you to change your mindset from highly ranked university to high quality of life (which is subjective and also includes a little bit the rank of the university, if you value this).