My professors conducted research in areas that were only slightly related (on a good day) to the material that they were assigned to teach. These people carefully preserved overhead transparencies from previous teachers that were cracked and faded. They obviously had little enthusiasm for their teaching duties, and my fellow students mirrored the excitement.
Some became prima donnas that flew into a rage in the wrong circumstances. Some actively preened their students for (low-paid) graduate research (not entirely suppressing a greedy desire to exploit). And some simply took apathy to levels that I had never seen before.
I went through a real circus with a professor going for tenure (who did have basic problems with competence) that had to endure not only the stifled laughter of fellow faculty in our class, but video tape recorders documenting his poor teaching style.
School, at all levels, needs to put people who want to teach in front of people who want to learn, which is diametrically opposed to the structure of a research university. If you don't have both of these types of people in the right place at the right time, the results will be substandard, as indeed they have been for the past century.
Fail the school.