Are they just trying to sell us seminars?

I follow several blogs of many respected photographers. I respect them, and I think that their work rocks. but it seams that a lot of what they do is to invite you to seminars. I think that they even complicate their lighting or whatever part of photography that they are famous for just to draw you in and make your jaw drop. so they are better than me and they do share knowledge, but they make my head spin w/ how complicated they make a simple task. just my opinion.