Evidence for what claim? What other option is there ? Unless you literally abolish capitalism there are going to be wealthy families that will have power. If you do abolish capitalism you will have a state run oligarchy in all likelihood - definitely worse. If you tax billionaires out of existence it would likely just result in them leaving the country and investing elsewhere. Its common sense. Large corporations, whether you like it or not, are the backbone of the American economy. California's pseudo welfare state is funded by the massive corporations that are headquartered there. Without silicon valley and Hollywood the state would collapse overnight.