Most people, when money comes in, they spend it on things, so it immediately has to also pay VAT. If they're lucky, they may have some savings, but it's going to be on the order of 2-3 months' worth of income.
Rich people make orders of magnitude more money, and mostly need to spend the same order of magnitude to live as the rest of us. The money beyond that, they mostly don't spend on the same kinds of things. After all, what would you do with a million dollars' worth of soap?
There's no VAT on lobbying, on buying a house in the Caymans, on hiring six people to clean the mansion.
VAT, like all consumption taxes that aren't highly targeted, is hugely regressive.