While this is superficially true, the structure of capitalism arguably makes such concentration of wealth and power inevitable, so the phenomena of monopoly and oligarchy are intrinsic features of capitalism. Not free markets, but capitalism, i.e. the system where individual, private citizens own the means of production.
I'm not sure yet whether I think that capitalism can ever be made work for the people (including the underclass that our society currently consumes as human fuel to keep the status quo). I think it's quite possible that it will foil all attempts to reform it. But we'll see.