Earlier quoted context omitted.
It actually makes much more sense to use a uniform sales tax: (1) If you spend more, you're taxed more. Obviously this is better for poorer people, who spend less, but also for rich yet reserved people, who keep most of their money in the bank (which lends it) and are earning an income (=productive). Both will not penalized. (2) It's much hard to raise, because people will just stop buying stuff, which is much easier…
Sales tax fails to capture the accumulation of capital, so (1) is kind of bogus. If you make 100 billion dollars and invest it you and several generations of your family coild live comfortably without ever working and your tax burden would only depend on your spending. A sales-only tax incentivized rent seeking, basically, because the rentiers pay the same taxes as the renters while accumulating capital.
You want billionaires to keep their money, because unless they put it under their mattress, they are growing the economy, which means lowering prices and raising quality.