I'd give the U.S. (and, by extension, much of the world) economy another 2-3 years of growth before it sputters again. As long as energy is cheap, the house of cards can hold its place for a while longer. Even chronic illnesses can last a long time. The spark that lights that fire will be energy prices, which are low now, and those low prices have been fueling economic growth in many parts of the world.
When you see oil and gas prices start to climb and begin another spike, that will when something breaks again. The entire economy is dependent on cheap energy, and when that is not available, the increased cost adds exponentially to the price of everything else, to the point where many companies cannot make money and many consumers cannot afford to buy much stuff. At that point, you'll get another look at the weakest link in the economy (whatever it is at that point), much as we did in the last two recessions.
Will that be enough pressure to break anything, structurally? That may depend on whether the price inflation is treatable or not. If the U.S. Fed is unable to keep the economy going AND stem inflation, then I think the Fed must tolerate the lesser of those two evils, which is inflation. If the economy does not keep going strong, then the U.S. will not be able to afford its debt payments while having any chance of growth. Also, inflation will water down that debt over time. And that, I think, is how the Fed will get out of this mess. But it will be left with far less power and far fewer tools to affect the direction of the economy. Booms will be stronger and recessions will be depressions.
All in all, it will be a mostly inflationary economy for the foreseeable future (dampened slightly by occasional periods of deflation). BitShares should benefit, as will hard assets such as gold, energy, and other valuable commodities. And an economy based on real goods and valuable services is, at the end of the day, a healthier one than something based on all this derivatives shit that doesn't add value at the end of the day.
Biggest risk: If China somehow fails, it will cause a worldwide depression. A poorly timed natural disaster could be bad news also.