Guess who is going to have the most profitable business?

No. The opposite. (For those who want to join one at all, of course).

I'm pointing out that when someone wants you to join a new MLM business, and you point out (correctly) that most don't survive their first two/three years and you want to join only a well-established one, and your putative sponsor says "Mary Kay was once a start-up", he's guilty of exactly the fallacious, mistaken logic described above, and the appropriate thing is to throw rotting fruit at him.

I'd have put it more strongly than you, but we agree completely, anyway.

Clearly joining a start-up MLM is just another way of stacking the deck against yourself, and the fact that Herbalife and Mary Kay were "once start-ups" - true though it is - actually isn't a counter-argument to that reality at all, though it's very widely used as one by people whose grasp of logic leaves a lot to be desired. Those same people, in internet marketing, with their same defective logic, advise beginners to go into "the biggest niches like "trousers" (or IM/MMO/dating/whatever), and avoid the small niches like "skating" (or whatever), because "those big markets are where the most money is". What they don't understand is that the fact (and it really is a "fact") that those big markets are where the most money is, isn't a reason for a beginner to try them, and doing so is actually stacking the deck against himself.

It's a small world!

I agree completely, Jack.

I've always thought (and often said, here) that the single biggest factor in becoming successful, here, is "developing the judgment to know who to listen to", and "deciding by whom one wishes to be advised" (as I've worded it in slightly different contexts). That's my own perspective, anyway. I earned nothing to speak of in my first 3+ months, when I started. The single thing that made the world of difference for me, between that position and where I was just another 3 months later ($3,000+ profit per month), was developing enough judgement (and guessing well, to be honest!) to be able to decide who to listen to, here. Being unwilling to follow the advice of successful people, or being unable to follow the right successful people, are more common here than they ought to be, for a variety of reasons. Among those reasons is the fact that there's very little "informational quality control" on the internet. Urban myths of internet marketing are very pervasive indeed, and continually propagated simply by their repetition. :p