Beyond helping the economy, taxing the rich helps the political system. Here is what Madison published in the January 23, 1792 National Gazette:
"In every political society, parties are unavoidable. A difference of interests, real or supposed is the most natural and fruitful source of them. The great objects should be to combat the evil:
"1. By establishing political equality among all.
"2. By withholding unnecessary opportunities from a few, to increase the inequality of property, by an immoderate, and especially unmerited, accumulation of riches.
"3. By the silent operation of laws, which, without violating the rights of property, reduce extreme wealth towards a state of mediocrity, and raise extreme indigence towards a state of comfort.
"4. By abstaining from measures which operate differently on different interests, and particularly such as favor one interest, at the expense of another.
"5. By making one party a check on the other, so far as the existence of parties cannot by prevented, nor their views accommodated.
"If this is not the language of reason, it is that of republicanism.
"In all political societies, different interests and parties arise out of the nature of things, and the great art of politicians lies in making them checks and balances to each other. Let us then increase these natural distinctions by favoring an inequality of property; and let us add to them the artificial distinctions, by establishing kings and nobles, and plebeians. We shall then have the more checks to oppose each other; we shall then have the more scales and the more weights to protect and maintain the equilibrium. This is as little the voice of reason, as it is of republicanism."
In short, allowing increased inequality of property creates political extremism and incivility, just as we have seen in the USA since 1980. Madison would have predicted it all, and it was just common sense to favor a welfare state and higher taxes on the rich. It is the death of republics and the bleating of aristocracy to allow the kind of insane accumulations we have witnessed in America in the past generation.
I know I've posted this before, but really, people need to take it to heart.