…at the expense of the rest of the world. If you built a perfectly legal way for companies to get billions of dollars of income into the US tax-free and all it requires is a holding company on your island, you can be sure that you're going to be a profitable little island in short order.
Do you really think they would still have the world's highest GDP per-capita income with a 0% tax rate if major international companies were somehow not able to exploit it?