Best case scenario, the products are OK, just 5 or 6 times the price they would be if the company producing them didn’t have to pay commission to 5 or 6 layers of sellers.
Worst case scenario, the products are useless / harmful.
Even the companies with decent products don’t sell a lot to end consumers - their entire business model is flogging the goods to the sales reps.
It’s one of the ways to distinguish the MLMs from normal commission based sales.
Susie the Sephora Salesperson (for example) gets paid commission based on her sales. She does not have to buy the products she is selling before selling them on.
Marie the MLM Marketer usually buys every single item before selling it. This is the case even with the MLM organisations that say purchasing isn’t necessary.
For example, Mary Kay is one of the oldest such businesses. They get people through the door by telling them they can sign up for a minimal sum but then tell people ‘you can’t sell from an empty wagon’ (known catch-phrase) and arrange for their ‘independent salesforce’ to buy thousands of dollars of make up each (generally with no consideration of their market or whether the product will sell).