Comparisons to the modern US aside, that's a pretty misguided analysis of Rome. The territories whose loss cost Rome the most economically were Africa and Gaul, and calling them 'conquered territories' is like calling Texas and California the US's 'conquered territories.' At some point in the distant past they were conquered, but their inhabitants considered themselves Romans, and the Roman government reciprocated. Rome didn't 'plunder' 'booty' from Africa any more than we 'plunder' produce from California.