To my experience, MLM is a great opportunity. BUT (yes, with capitals!), since I'm somewhat experienced (having my third MLM business and started my first back in 2003), I'd like to mention that it's for everyone and... just not for everyone. That may sound controversial, but it's true.
MLM is a very specific kind of business. My husband is educated in Marketing. It's only since two years that he finally accepted that MLM in it's core, is a better way to make money than any kind of marketing for a "regular" business (some exceptions, of course. I mean, how can I ignore Amazon, Bol, Coca Cola, Apple and a couple of others... ).
Most MLM systems are so easy to follow, that everyone should be able to do it. In reality, not everyone will, solely because of fear. The don't get it, they don't believe it, they don't know what they would do if they'd make the kind of money possible with MLM, and because the principle of MLM is so different from everything they've learned so far.
And from those who do take the step and participate in an MLM business, some of them will get stuck being a customer, some of them will quit because they can't handle the change of mind most people need to make, some of them will make a nice extra income by selling products and/or by building a downline. Only a handfull will be dedicated enough to learn and do what's necessary to be actually succesfull.
Even though the MLM business I'm participating in is extremely easy to understand and to work with, I see that people tend to underestimate the work and the mindset that is needed to get going in a MLM business. Only after building a solid base, you can relax, take a step back and watch the snowball growing while rolling down the hill. It totally depends on your character, your skills and your efforts how soon you've build your solid base.