The problem is we're no longer special. By spreading capitalism and democracy across the globe we no longer hold a monopoly on this advantageous system. It was easy to out compete communism, they were playing with one arm tied behind their back due to their flawed system. It is much harder to out compete fellow capitalists, especially ones that are far more determined and hungry than we are. There are over 2 billion people in Asia who want their fair share of the limited global resources and they're willing to fight (economically at least) to get them.
Maintaining our advantage over them, especially in terms of resource throughput will become increasingly difficult. Huge increases in price of all commodities over the past few years have lead to significant inflation as the developing world outbids us for supplies. This trend is unlikely to reverse anytime soon. It will inevitably lead to lower disparity between standards of living in the US compared to other nations. It will also mean that achieving the "American Dream" will require people to work harder/smarter and may even become out of reach to some. There will certainly be more people who are classified as "poor" rather than everyone not homeless being considered "middle class". Free rides will be much harder to come by, especially for the lazy and the stupid.
One way for us to improve our chances of maintaining a high level of global power through this transition will be to radically reduce the material throughput of our economy. Economics is not a zero sum game. Someone else getting richer does not necessarily mean that we have to get poorer. While there is a finite amount of iron, copper, land, oil, coal, etc., there is not a finite amount of technology, knowledge, entertainment and other services. To a degree we're already making that transition. However, we also need to make the transition to lower impact daily lives as well. We need to use less energy, we need to buy products that are durable, not just inexpensive, we need to increase recycling, we need to invest heavily in domestic renewable energy. All of these things would reduce the amount that our economy and daily lives are exposed to commodities that we will increasingly have to compete for. By doing so we limit the amount of pain that we will feel as a result of the inevitable growth of the rest of the world.
If we fail to adapt we will suffer the consequences that befall any nation that fails to adapt to a new reality and it won't be pretty. Luckily one advantage that Americans have always had is our adaptability. Lets all hope we haven't lost that too.