Exactly. Another thing to consider... it's entirely plausible for nations in a fantasy world to differ from the patterns found in our world. The culture, history, social structures, and scientific and technological advancements can be - and are - completely different, even at odds, with what we have in our world. Large-scale self-sufficiency, as Besimudo described, is by no means an impossibility. Our entire world survived for millennia with no trade between many nations, after all.