Everyone involved (except the simps) are making money hand-over-fist as far as I can tell so it checks out.
It is a perfect storm of the world's oldest profession meeting lonely simps looking for ways to spend their money for validation from another human. Bonus modifier is that the performers don't even have to be attractive.
At this point, I'm sure they have studied the ways to get people to spend more money and likely have it down to a science. From what I've seen, when a performer starts saying things like "you guys are making me cry (with how much you're giving them)" it triggers something in people to give them even more. Things like that.
It's quite a study in sociology, manipulation, and marketing. I can see why your friends would have talked about it where it sounded like a stock market.
They know exactly what they are doing.
This:
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It's also nice that their costs are basically zero after initial starter build. The fan-art alone that they have got already could sustain them for years to come.