"Are you saying that Romans were in the same economic system than Spanish? Yet the same general rule applies."
I'm saying no one, even during the 'globalization' of the early 20th century, was in a comparable scenario. So, no, the same general rules don't really apply. We don't have to take from someone else to grow our economy. There isn't a finite global GDP pie. We aren't a tiny population militarily subjugating our far-flung lands and drawing revenue from them. For every 'similarity' you can cite, it can either be reduced or off-set by a long line of differences.
Not if you don't count the roughly 2 billion dollars a day of foreign investment. Someday those Chinese, Europeans, Saudis, etc may want their money back. And it is still their money.