I agree with the premise of what you're saying here overall, on the contradiction you pointed out, and that sales tax is a regressive tax, and about the rich being a dominating minority etc.

One thing I'll add is that extremely wealthy individuals tend to have modest or even low income from wages, so relying on progressive income tax brackets alone still results in a tax system that is either flat, or not progressive enough. Progressive income tax is a smart choice but it doesn't go far enough IMO. Wealthy families gain an enormous amount of money from unrealized capital gains, dividends, and interest, all of which enjoy huge tax breaks.