Is America A Plutocracy?

On the heels of the tax cut extensions comes an interesting article by Francis Fukuyama, which muses on why there has not been a populist push from the Left regarding the increasing disparity between the very wealthy and the rest of us...

We therefore raise a different and more interesting set of questions regarding the relationship between money and power in contemporary America. All these questions come together, however, in a paramount puzzle: Why has a significant increase in income inequality in recent decades failed to generate political pressure from the left for redistributional redress, as similar trends did in earlier times? Instead, insofar as there is any populism bubbling from below in America today it comes from the Right, and its target is not just the “undeserving rich”—Wall Street “flip-it” shysters and their ilk—but, even more so, government policies intended to protect Americans from their predations. How do we explain this?

I wonder if the primary cause issn't the lingering belief in the American myth of "upward mobility" -- that with sufficient hard work and effort, anyone from any background in America is able to "pull themselves up by their bootstraps" and become one of those very rich themselves.

What are your thoughts?