Professors often don't have students' best interests at heart. Why should they? After all, once they have tenure, they can't be fired... Professors sometimes abuse this power, such as when they choose textbooks based on kickbacks they get from publishers. And have you ever wondered why all the "good" classes are held at the same time, in the middle of the day? Possibly it's because those tenured professors want to come to work late and leave early. The result? You can't get the class you want. And even if you got it, you might not learn much. Faculty members generally aren't promoted based on their teaching skills, but rather on their prestige and the research dollars they generate.
(From the same Thomas Sowell below - who is a professor himself.)
And to the extent that you can generalize that professors in big-name universities are more focused on generating research dollars and upkeeping prestige, this would confirm my observation all along that »my professors at Madison were much better teachers of economics. It would also support why in terms of selecting classes, you should not let titles ("lecturer" vs "professor") affect your your choices. (Some of my best classes were taken with »this memorable lecturer.)