It does, but at that price point you can start paying lobbyists and politicians to help make sure it doesn't happen. Likewise, at that point you can have your money stashed in a tax haven or other financial constructions to make sure you don't have to pay taxes, even if there was such a tax rate.

The marginal tax rate might help the American poor, but for the rest of the world, where the majority of poor people are, this, on its own, isn't really going to do much good.