Harvard Professor Niall Ferguson does an analysis of societal collapse for "Foreign Affairs".
He begins by discussing "The Course of Empire", five paintings by Thomas Cole which depict various stages in the life cycle of a society. The paintings are set in the same location and show in succession a river bank in the wild with aboriginal people, a simple farming community with a large columned temple in the background, the temple turned into a palatial city with ships coming up the river, festive activity, and opulence bordering on decadence, the great city being ransacked by invaders, and finally the overgrown ruins of the city with no humans in sight. This closely parallels the history of Rome over a period of maybe one thousand years.
Ferguson then makes the argument that in spite of the narrative suggested by the pictures, the reasons for a society's collapse are more incidental than structural. Instead of an inexorable calamity years in the making, a civilization's demise can be brought about quickly simply by poor management and decision making.
I disagree with this as a general rule and I think he misses the point as to why the explanation brought to mind by Cole's paintings is so compelling.
First of all, I don't deny that terrible government can quickly destroy a society. However I think this is less likely for society that has the staying power to become an empire; there must be some inherent stability and redundancies present or it never would have gotten this far. But the story of the nation with simple beginnings grown into a behemoth that overreaches is very believable because we have so many examples of this pattern.
Ferguson says that if Rome had been better managed and had the sense to take preemptive military action against the Vandals, or had raised taxes to pay them off again, maybe things would have turned out differently. I think he ignores the fact that the character and characteristics of the Roman empire at that time guaranteed that if they avoided one danger, another would soon come along and eventually they would succumb.
Rome's size alone made it vulnerable. It was slower to adapt, harder to govern, and harder to defend than when it was a small settlement. Its success led to a softness that became a weakening of character, so that it was more difficult for its people to accept hardship.
Does this mean that it is impossible to be successful without being doomed to eventual catastrophic failure? No, but I think you have to consciously avoid the temptation to take the easy way out at the pinnacle of success. Therefore this is not common. Most people will not voluntarily check themselves or undergo some hardship when they don't have to. But this is necessary because growth cannot continue forever.
I think Great Britain is an example of a fairly graceful transition from world power to world nation.