once the money is in a billionaire's pocket, you will never see it again. you have to tax income as it flows, because otherwise it is heading offshore. sales tax won't help: they will buy their megayachts in a jurisdiction in which the rate is zero. and the claimed social benefit of lowering tax rates will be a straight loss.
so it's back to the cycle in which the middle class lose, but apparently haven't the insight to see how the game is played.
i guess an alternative to income tax would be to insist all business is accomplished through a separable enterprise and then tax that rather than personal income. you'd need to refine the current system, though.