Multi-level marketing is a kind of pyramid scheme, they're only legal because existing anti-pyramid scheme laws only prohibit "businesses" that don't actually sell any products, and make all of their money through recruitment.

MLMs get around this by recruiting people to "sell" products, but recruits must pay for them in advance (almost always at a massive markup) and the products are typically so overpriced and/or poorly made that many of them go unsold.

So, almost all of the profit of those at the top of the pyramid comes from their downstream recruits recruiting more people to "sell" the product, even though product sales are completely unrelated to the success of the scheme as a whole.