I think the only reason the US continues to exist in its current state is due to the global power of the US currency. It is the dominant currency for international exchange, which gives the US government extraordinary influence in international affairs AND gives corporations and wealthy people a reason to be based in the US. There are historical similarities with other countries having a dominant currency such as the British Pound or Dutch Guilder during those countries periods of imperial dominance. The empire is likely to persist as long as the currency remains dominant no matter how badly it is mismanaged.