To be fair to the professors, they wouldn't be teaching intro to whatever if they weren't genuinely enthusiastic about the subject. Also, while the ROI on some

To be fair to the professors, they wouldn't be teaching intro to whatever if they weren't genuinely enthusiastic about the subject. Also, while the ROI on some majors is terribly negative over a large population, that choice has likely worked out very well for the professors teaching the class. A tenured position at a major university is the closest you're ever going to get in life to a sure thing.