I found a site through a Google search
that had some indicators that a MLM is not going to be profitable or that money is not being made on sales of product to customers if certain criteria exist. Paying beyond I think four levels, they said they profits are coming from overpricing product and purchases made by those in the MLM. And it is an MLM if it has levels and layers of commissions and bonuses.. can’t really argue that.
Don’t remember the site but they showed up in the top page of results, so they would be easy to find if you searched for it.