From personal experience, many professors are more interested in themselves and forget that the primary mission is the development of students. I've seen this

From personal experience, many professors are more interested in themselves and forget that the primary mission is the development of students. I've seen this mistake a lot. While you may believe that the primary purpose of professors is teaching, this is not true at many institutions. In fact, at heavy research institutions the benchmark for tenure is not teaching performance, it's grant success and publishing.