They know they can't possibly make the sales required to earn sufficient commission. They are told that from the outset, conversationally. Whether that be 'You need to recruit team members' or 'managing a team is a gamechanger....'
What isn't obvious, close up, is that there have to be losers for this to work. No matter how far down the chain you are, there needs to be someone more desperate than you who is willing to take the risk of losing money, to be your 'team'.
Take Avon as an example. They get 20% 'commission' or 'discount' if they've put in an order over £80. But, that £80 is the ex.VAT value - so the customer order value is £96. If they place an order for £150 ex.VAT, they get 25%.
However, they also need to factor in brochures, bags or samples. So even then, they will lose out of that commission.
The 'key to success' is to get to a point where their sales don't matter. If they recruit enough downstream team members, they get their own 25%, plus 2-6% of their downstream team's order value. Then there is another layer, for people who manage to recruit team members who then create their own teams, and so on.
The notion is, that eventually, you can place an order for anything - give the stuff away - to meet your minimum order value, then your real earnings come from the commission earned on the orders of your team members.
The dream they are selling, is that you are essentially just going to chat to a few team members to keep them motivated, and they will do the hard graft of selling.
It doesn't work, because of market saturation, etc., but there will be those, like Gail Reynolds who started 18 years ago and has built her money on the back of people who tried to follow.