My aim was to suggest why minds and cultures that seek happiness through wealth/power will tend to spread, in part because gaining wealth/power in fact yields no satisfaction or lasting happiness. Words and ideas I offer here may be used freely and without attribution.
That would be my take on it too. I think it starts with a military advantage, which can then create a positive feedback loop where there's an interest in empire building.
But there's another angle, which is how economic and political domination as a substitute for physical warfare. US interests are no longer served by sending in the marines and killing anyone who refuses to pay tribute.
Instead there's the World Bank and the World Trade Organisation, which set trading terms favourable to the US and make military action in pursuit of US interests less necessary.
5th Century Rome was incredibly wealthy in local economic terms, but was taken down by bands of nomads who considered themselves lucky to own a wagon.
Some of the tribal groups had a numeric advantage, with migrations that literally stretched across entire countries.
Others had a huge advantage in military skill and tactics - including better technology, with a short bow that could punch through a metal shield at a distance of hundreds of yards.
Conversely when Rome originally started to expand, its only advantage was military. It wasn't any richer than its neighbours, but it knew how to put together and drill an extremely effective citizen army.
Today if terrorists had more imagination and skill than they seem to have, it would take very little money to do huge, even terminal, economic damage to London or one or more major cities in the US. An insignificant fraction of the US military budget would be more than enough.
