Sure there are lots of charlatans out there, but there are plenty of teachers who really believe in their content and really want to help people. Some people love getting in front of a crowd to do a seminar. Am I going to begrudge someone who's found a way to make money doing something they love? As long as they're doing it in good faith, who am I to judge?
Lots of people write books or create courses because they feel like they have something to say. Let them say it. Call out the charlatans as charlatans, but there's no sense in mocking all teachers.
(I suppose I ought to admit that I am a university professor; however, I actually agree with some of @Tim G.'s statements about colleges being the biggest gurus of them all. I'll just add that the teachers at colleges don't see much of the money these days.)
