[ebalit]

Riches have more to gain from a working society and more to loose from a failing one.

Or as Adam Smith puts it: "Civil government, so far as it is instituted for the security of property, is in reality instituted for the defence of the rich against the poor, or of those who have some property against those who have none at all."

In that sense, it's quite natural that the richer you are the more you contribute.

It's interesting that in your example you seem to tax wealth and not income. I don't know of any country in which the tax system is based around wealth and not income.

And indeed, a flat tax on wealth would probably be the fairest tax, but I imagine that it's a lot harder to do than taxing income or consumption.