Same for Rome, Turkey, Mongolia, Russia.................
Many world empires have come and gone hun, it is the nature of thing.
However, there is still the commonwealth, and countries are still quite pleased to be in it.
Military might really isn't the clever way to go anymore, economic might is, and there are quite a few gentle giants in the world that are just biding their time, India and China for example.
The American economy is quite dependant on manufacturing in China when you think about it.