Do you know anyone who has been successful at multi level marketing?

I have met someone selling a decent product. She is one of the most optimistic people and is incredibly driven to be successful at building sales and a team.

When I run into people like this I just shake my head and think they are doomed to burn out before making any money. The sales network for this product is fairly saturated. I would rather not disclose the product to keep the answers focused on the probability of success with this type of marketing.

Given the individuals drive and personality I think she just might do it.

Have you known anyone that was significantly successful at this?