I've only been to Burning Man once but based on my limited experience, you can have whatever experience you're looking to have there. It's different for every attendee. Some go for drugs, some for yoga, some for music, some for the art (which was incredible and completely exceeded my expectations), some for the community, and some for many more varied reasons.
If you want your Burning Man experience free of techies, models, celebs, and billionaires — I assure you it won't be a hard feat to accomplish. There are myriad subcultures within the culture of Burning Man.
I wonder if they picked that name ironically. Sherpas are probably best known for being porters and guides for Mt. Everest, a mountain that many in the mountaineering community consider to be, now, a playground for the rich.
Because I never get tired of this fun fact: the Sherpa people have a great tradition of building new homes as a community whenever a marriage occurs, as Sherpa families generally are quite large and live together until such marriages occur. This is generally a pretty intense process, since the culture has a huge emphasis on household deities and that kind of thing [^1], so houses (and land in general) is a big deal.
I'm not saying that being a professional mountain climber isn't super impressive, I'm just saying that if there was only one thing we could steal from their culture I wish it was less about making it easier to reach high elevations and more about building things together that last decades.
[^1]: I don't mean to be dismissive, I just don't know that much about their religious beliefs.
And yet, nearly all of the subcultures shared a few commonalities. Some had better food than others, a few had air conditioning, and nearly all were cut off from the rest of the world.
I can easily see the motivation for some creature comforts, but the harsh circumstances of being in the middle of the desert and the lack of technology in general are what help make Burning Man so drastically different from everyday life.
If you want your Burning Man experience free of techies, models, celebs, and billionaires — I assure you it won't be a hard feat to accomplish. There are myriad subcultures within the culture of Burning Man.