Does the US not have double taxation treaties though? In some places you can just create an offshore company, tax your profits in a different legislation, and then be exempt from further taxes under your own legislation due to the treaty as you've "already paid them" (even if the taxes are as low as 2% or even 0%).
That's why a lot of rich people all over the world choose Monaco for the residence. They pay lover income taxes there and don't pay in their domicile country. Nobody pay's income tax twice, can't believe it's current US law.