Your experience is wildly different than mine then. The worst professors I had were the ones teaching out of their own book.

Definitely one of the worst classes I experienced was Thermodynamics where I had to tip-toe around calling out gibberish in the 1st edition book authored by my professor. He was a real hard ass that would make you feel like the idiot for asking why the book and the whiteboard don't match.

I had this same experience. The professor would say just read the book. We would say but we did read it and we are confused. And he would say I don’t understand the issue it’s very clearly stated in the material.

In fairness I actually did have one good experience with this. I had a history professor assign some material he’d written about the civil war and both he and the material were fantastic. Ironically that was at the junior college. Professors become professors by publishing. I’m not sure why someone would think “wrote the course material” would be a feature unique to elite universities.