I find this kind of issue with conferences generally, in many subject areas.
I find that I can get more detailed and expansive information from a book for a vastly smaller price compared with attending a conference on the subject.
Also, many papers are published after a conference. So, I just save the air fare and hotel costs and buy the book!
I don't get it. Perhaps the main point of conferences is the coffee breaks, rather than a keynote address.
