They all want to sell you their books, DVDs, live courses, etc. Seriously, this RSD group you mentioned offers three-day bootcamps for $2,000 - $2,500. That's one-tenth of the annual tuition for a private US college, and they charge it for three days!

The books and DVDs thing is a problem, yes. AIUI, it is quite possible to find high quality free information, but it takes some looking around.

As for the bootcamps; these are some of the highest-profile events in the PUA community. Also, assuming that they actually work with reasonable probability and also generalize to a sustained improvement in social skills, economic/monetary returns for the participants might suffice to justify a significant fraction of that cost.