With GDI you have to pay taxes on what you make at the end of the year, here in the USA.
Pyramid Scheme you don't.
Don't you have to pay taxes on what you make in other countries?
So what is wrong with a pyramid scheme? All businesses are pyramid in shape to some degree . Even GDI. The problem is some are legal and some are not. I must confess that I have a lot of fun when someone says that GDI or any other program iis is a pyramid scheme, only to find out the person making the claim is involved in their own pyramid scheme, maybe as a school teacher, a church minister, a Police officer or a store clerk.
And try and tell the IRS that the income you earned from a pyramid scheme is not taxable, legal or otherwise. All income is taxable. After all thats how the US government got Al Capone in the end.

A good rule of thumb, is that Legal pyramids sell commissionable goods and or services.
illlegal pyramids sell people.
Regards
Bryan