Money is simply a representation of value. If you can create value out of "thin air", or even the perception of value out of thin air, then you can make a profit. That much has always been true.
What gives the C-Corp shares value, particularly the ones that trade at very high P/E ratios? Speculation on future growth, speculation on potential dividends, speculation on favorable market conditions, speculation on quantitative easing bringing yet more trillions flowing into stock market, etc.
What's interesting to me, is that people think our US Federal Reserve fiat monetary system is not an MLM scheme in the same way. We know who profits from the existing system: the older participants who got in early. We know who's been totally screwed by the current system: millennials and Gen Zers who can't afford housing, saddled with debt, living with their parents in their 30s:
https://www.pewresearch.org/fact-tank/2020/09/04/a-majority-...