Oh no it's clearly mutated into an MLM. I found it interesting how it turned into one last minute. In a lot of ways it is the logical next step for this kind of product.

Doubling his/her revenue in 2 months shows how powerful MLMs are.

I don't think there is anything inherently unethical in MLM sales structures, it's really just how they are run. The real problem with most MLMs is their core business doesn't work, they only work by sucking money out of those unsuited to succeed selling the core product.

That would be the case if referrals were the only source of income.

Not an MLM, see other comments for more details.