As long as the Fed can keep printing paper money, they can keep it going - because the populace isn't paying attention, and most likely never will.
That will work only as long as someone is willing to buy our debt. China has been a willing participant in this endeavor, but lately they've begun to stumble, so who's left to take up the slack?
You're correct about the population paying attention. I agree with Gruber, most are stupid, but sooner or later when the well runs dry, they'll be forced to face reality.