It appears the system has always required plunder from outside its borders in order to sustain itself.
All empires do this.
USA, UK, Japan, China, Russia, USSR, the Roman and Ottoman empires, many European countries. It doesn't matter whether the rationale for the empirical ambitions and practices are commercial, ideological, racial, religious or mere competitiveness (see European history of exploration/exploitation). And it doesn't matter that some tinpot prince of a remote province claims to be the omnipotent emperor of half a dozen villages and a yard of donkeys or that some modern entities claim not to be empires at all - China, Indonesia, USA ..... the result is still the same. Expansion, exploitation, expropriation, trade, war.
No empire, country, region, city can sustain its power and growth without obtaining resources from elsewhere. The resources required and methods involved vary by time and place, but the principle never varies.