Burning Man is a giant art party in the desert. It's becoming increasingly expensive in part because it's been increasingly popular, and so requires increasing facilitation (i.e. a temporary medical center complete with a radiology setup). Everybody that attends influences it, even the very wealthy, and the more interesting among these direct their influence intentionally by funding art and performance which anybody can experience.
Yeah, i'm not sure that would even be appreciated. Full disclosure: i was at the Iberian Peninsula Family Gathering in '11, and i haven't been to Burning Man (am kind of motivated to, though, in a sort of long-term TODO way), so that's my experience, but my impression is that the mentalities are rather different... I feel the Rainbowers kind of like their toned-down way of doing things (e.g. explicitly no stereo systems)...
Million dollar sound systems, pyrotechnics, and the kinds of people who can make that happen aren't going to show up at a Rainbow Family Gathering anytime soon.