america's wealthy own most of the wealth because of the federal reserve being created and introducing the 'inflation tax', which causes 'trickle up economics'. this is where the wealth is slowly and steadily forcibly taken from the lower/middle class and centralized to the wealthiest - who gain access to the government printed money the earliest which they use to make moves in the market. the rampant collusion of business with government and the socialization of business losses on the taxpayers sure as shit hasn't helped, either.
in a truly free market with sound money and government not interfering in markets, you'd see a much broader spread of wealth. this is what created the large middle class in america - the decline wasn't because of capitalism or lack of regulation.
the people advocating additional taxes on the wealth are completely ignorant of the fact that the wealthy will gladly pay the tax, and get it right back just like they've always done. it would be a very short term, short sighted attempt at fixing a problem which doesn't exist, while ignoring the fundamental corruption of our system. end the fed and restore sound money, and the wealthy who steal the wealth with their politician buddies will no longer have a vehicle with which to do it.