I do not think that many disagree with that conclusion. But where the article surprised me is when he talks about the potential failure of markets:
Anti-capitalist virulence appears strongest from those who confuse “crony capitalism” with free markets. Crony capitalism abounds when government leaders, usually in exchange for political support, routinely bestow favours on private-sector individuals or businesses. That is not capitalism. It is called corruption.This is the only sentence in the article where Greenspan admits that there could be some failure in a market economy. But that failure is driven by bad government behavior! Other than that, markets work fine. I hope his views are not really that extreme and that he is willing to accept some of the market failures that economists have identified in the past and that are taken care of by different forms of regulation. This is to me the interesting debate, the one that identifies market failures and then tries to address them via intervention or regulation. In that debate we might find that government intervention is not always possible or efficient. And I am sure we will find disagreement on the domains where government intervention is necessary or optimal. The other debate, the one that compares "capitalism" with the economic system of the former Soviet Union does not sound too interesting or useful at this stage. And it only leads to statements like the one above that seem to be driven by faith in one of the two systems.