I've never been to Burning Man myself, but I'm aware of the event due to Drizzle development stalling to a halt during that festival. In other words, I have many friends that go there.
It was interesting to read a statement from the organizers of Burning Man about the fact that this year there is way more demand for Burning Man tickets than they can sell. Apparently even the desert has its limits (and more so the road leading to it).
Organically growing volunteer projects are exciting because they just grow and grow and there seems to be nothing there to stop them. But once in a while they hit bottlenecks that need to be solved.
When Linux development grew there was a lot of tension which is today known as the "Linus doesn't scale" debacle. Basically Linus was burning out while everyone else was unhappy for him not grinding their patches in faster.
The solution to this bottleneck was the introduction (dare I say invention?) of distributed version control (bitkeeper, git). It allowed the Linux development process to continue scaling to new heights, plateuing a few years later at 1100 developers per month and 18 thousand lines of code edited each day.
Otoh when Wikipedia became popular they invented processes such as "deletionism" to guard the quality of their online dictionary.
The lesson here is that phased with a problem, an engineer will invent great things and a humanist will invent bureacracy. It will be interesting to see how the artist-engineerish Burning Man crowd will solve their bottleneck.