End of the day, no one has been rich because of the products working well. The top tier ones are earning big bucks by promising their downlines that they will make big bucks if they find more and more friends and etc to be distributors. Also by giving so called "complusary" talks and seminars which are chargable. End of the day the top tier laugh their way to the bank and the rest work to make the top tier rich.
End of the day, MLM appeals to the basic human instinct of greed and laziness. Promising one instant monetary gains with no need for capital nor hardwork, no wonder so many gullible people fall victim to it.