GDP is a modern concept made to measure today's economy. But if you talk about power US is the most powerful country but not dominant (see Syria and Crimea). T

GDP is a modern concept made to measure today's economy. But if you talk about power US is the most powerful country but not dominant (see Syria and Crimea). The British empire at his peak held one fifth of the worlds population. The Roman empire conquered everything was worth conquering and he was providing free food and gigantic games to his poor citizens. If you consider modern Europe his GDP is very similar to the US, although his political situation is more fragmented. So back to the OP in each era the economic conditions improved, and there was a place where this improvements was more evident, a country who was richer and more powerful than the others. US is one of these nations but it's not something exceptional in history as the OP suggested.