I completely agree and am thankful for the professors who take their teaching job seriously. To look at it from the opposite perspective, I dropped out of (a very good, top five in my field) grad school because I realized I wasn't brilliant and realized if I entered an academic career I would basically be a teacher. And I suck at teaching. And I had little interest in getting better.

I had other reasons for dropping out and have sometimes considered the above to be just a bad justification for a bad decision, but more and more I think that whatever my true reasons, it was a valid reason and a good decision. It would have weighed me down knowing that I was actually pretty bad at my primary productive role in society.