Classical liberals and libertarians of course run with a different -- IMHO utopian -- definition of capitalism which puts the emphasis on the act of individuals trading goods with each other. From my perspective it's an ideological smoke screen which papers over the reality of the asymmetrical distribution of power that arises naturally out of the particular 'natural rights' of property that classical liberalism embraces. And they were embraced historically precisely because of that distribution of power -- during an era of expanding colonialism, imperialism, and enclosure.
To put it another way -- the US may not look like a textbook laissez-faire capitalist society that a Friedman, Hayek or Randian would advocate -- but the unjust power structure of the US and societies like it are what actual-existing capitalism _creates_. It is capitalists who rule, and capitalists who made it that way.
Why stubbornly claim capitalism is a failure when America is not capitalist? It is not laissez faire capitalism, like Chomsky says, it is a nanny state, where government bails out failed business. That is not capitalism.