It now includes members of the Silicon Valley set and their trappings, as well as a simmering sense that it has sold its soul. Yet for the cottage industry that supplies its outlandish costumes, the influx means one thing: a bumper year for retailers of spandex and faux fur.

“It’s a place where you can do whatever you want and not feel like, ‘Why is that woman’s side of her head shaved?’ Or, ‘Why is that person’s hair blue?’ ” said Joe Carter, 35, a musician and a longtime Burner who favors his custom leather suits in the style of Jimmy Page of Led Zeppelin. “None of that matters up there. The societal norms melt away, and inhibitions melt away.”

The term “cosplay” — or costume play, usually with a role-playing element — emerged in the 1990s from Japanese anime and theater, and it has been widely embraced by Burners. Although adults also don elaborate costumes at Comic-Con conventions and similar events, the garb worn at Burning Man tends to be custom made and built for repeated wearings. Few, if any, off-the-shelf superhero capes or witch wigs are to be found.

The extravagant costumes in the Black Rock Desert help with another escape: from reality.

A multiyear study published in 2013 looked at the psychological effect of Burning Man on its participants and found that people there were more comfortable expressing themselves, particularly positive emotions. The costumes, said Kateri McRae, an author of the study and an assistant professor of psychology at the University of Denver, could be a reason.

Image Ms. Rendon sewing one of the custom outfits at the store. Credit... Jim Wilson/The New York Times

“The clothes may be a sort of cue that the rules are different here,” she said.

On Haight Street, corsets, top hats, mirrored umbrellas and a particular Burner favorite — low-slung leather utility belts to hold desert necessities like lip balm and electrolyte tablets — hang in many windows under signs that say, “Burners Welcome!”