"That being said, the very nature of the event involves spending thousands of dollars to live in the desert for a week. So the audience is obviously mostly people who have the money to do so."

It depends what standard you need, but I have been to (way smaller) desert gatherings where people with no money came. (Not as remote, though, possible to walk there with a tent). But as far as I know, the main thing you need for burning man is a van and water, or know someone who has one.