That's more a reflection of just how thoroughly the left has been destroyed in this country. It doesn't exist as a single, united movement. You have the Green Party, social libertarians, various form of anarchists, socialists, etc. What is pretty clear is that a backlash against corporate greed certainly has overwhelming popular support in the United States, but a clear-cut, equitable, permanent solution to the problem has not been widely expressed. When that happens, I imagine something akin to a new Bill of Rights could be fairly quick in materializing.
Until OWS started to build a sustained presence in multiple cities, the actual left may as well have not existed. And yet, people aren't afraid of advocating socialism anymore. A century ago, these sorts of protests gained military responses, sometimes against the families of protesters rather than protesters themselves, and handing out communist pamphlets could get you arrested.