A family member got involved in an mlm about fifteen years ago. I found it fascinating because it was pretty clear to me that there was no way you could individually shift enough product at enough of a mark-up to generate anywhere near the turnover required to generate a decent profit.
Her average sale was about £15. To make £250 a week in turnover, she had to make 17 sales a week, so at least three a day (or £45 worth). Her markup was only something like 20 percent, so those 17 sales gave her a weekly profit of £50.
To get anywhere near reasonable earnings, say £200 a week, she had to sell four times that amount, so nearly 70 sales at £15 a pop. For a home-run business with no ability to flog online, increase mark-up, shift product in bulk, and no bricks and mortar store front, it was impossible for her to generate those kinds of sales.
Even if she had a stream of people coming to her house and each sale took 15 mins, she'd be looking at spending 17.5 hours a week solely engaged in the process of transaction. This would be the equivalent of spending three days a week solely receiving customers constantly from 9am to 3pm without a break.
It just wasn't going to happen; the demand just was not there for such a set-up. But it was only DH and I that seemed to be able to see this.
I think one of the problems is that people believe the hype surrounding a lot of these mlm "opportunities" and they don't break down the figures. If you can't sell enough product to make it work, then your "downline" will not be able to either, so taking a cut of those profits won't amount to anything much either.