I'll take a quick shot:
While there certainly should be no penalty for being successful, I see it, as such, as an extended way of giving thanks...
Think about it:
When you're poor, you don't usually pay many taxes below a certain povery line, and you don't give to free will, you get.
Middle class, you tend to pay more taxes, and give back more in taxes, both because you ahve more to give and because, presumably, you have benefited more from the State's existence.
Hence the reason the Wealthy should pay the most:
Without the State, the Wealthy would have no protection for their goods, no public roads along which to spread their trade, fewer customers--as if there's an unstable state-of-nature about, no one is apt to be civilized and pay and be nice for necessities, to say nothing of luxuries--amd so on and so forth.
The Wealthy are Wealthy due, in part, to their ingenuity and use of the lower classes--please note I DON'T see tht as a terrible thing--but also partly because of the existence of the State, as the State gives them a market and security and the start-up civilization necessary for trade and commerce to begin with.
As such, as the Wealthy owe so much to the State, and they can afford to give more back, it seems fair and itting that they give the most back of any of the three classes.
That being said, PENALIZING them for being wealthy or instituting any sort of "wealth" cap, por redistributing their wealth to help the other classes directly is NOT supported by me; the increased taxes must help the State as a whole.