Network marketing is based on the premise that nothing is more effective than referral sales. It is recommended to people who know. So if I like Brand X soap and I say I like it and they have to try it probably will. It is true and will always be true.
In the early days of MLM, there were a lot of actual sales costs, advertising costs, demonstration product delivery, salespeople, and payments, and the idea of turning customers into salesforce was unique. Significantly reduced sales costs and provided revenue opportunities for customers.
Over time, things changed. A few years ago there was an intersection where it wasn't cheaper to reward a tiered decentralized sales force than to sell directly to customers using the Internet.
It's really hard to build a “successful” MLM business unless you have a margin that's marginal (nutritive, vegetable, etc.) on the products you're selling or a front tier of multiple planned follow-up products that will appeal to your original customers.
The big problem with most MLM companies nowadays is that some of the larger sales volumes is for distributors/operators for "stock". So they got such a terrible reputation. You don't want to use it, but you have to demand it as a condition to stay "agency". And there is no actual "customer" sale. Nobody buys products that aren't "business."
And the Internet has made it impossible to kill people with complex binary reward packages. It is easy to find out what it means, how it works, and that the small print is basically "you will never get paid because it is impossible to balance your legs to do such a workout". There is also a "descriptor video" that people explain for this.
If you find an opportunity with real customers who are not in business, it is worth looking into.
If you were there and wanted a frank discussion with the person who did the job (80s Diamond Level Amway, some success after that), you can leave a note and promote the introduction.