I know a big criticism of The Hunger Games was the fact that we never learned what happened to the world outside of Panem. The other night, a friend and I began talking about it, but neither of us are very well versed in economics or politics.
In theory, if the United States, government, economy, and all, were to collapse, what would the effect be on the rest of the world?
Government, economy and all? Given the interconnectedness of the world economy, you can likely assume that general chaos and regional hegemonies would ensue, largely enforced by military assets to secure vital resources (oil, gold, food).
How much of the Chinese economy is based on production for the American consumer market? How much of the ever-increasing telecom and IT outsourcing is getting pushed to continental Asia? How much of the current economy is completely dependant on the electronic transfer of funds? How much of that is tied to the American economy? The short answer is: much. That said, recent economic/political pressures from the EU and the faltering American economy show that it doesn't take a total collapse of a state to put economic cycles and stability completely out of whack.
In effect, the American economy had become something of a hegemon due to the importance of their economy to global financial security and stability, the importance of the US$ in exchange and as national reserves the the dominance of American financial institutions. One could argue that the Chinese are a growing proto-peer, but the Chinese economy is both integrally linked to American economic success and a significant holder of American foreign debt and currency. You lose the American economy, the shock to the system is likely too great a strain to handle.
This is actually somewhat related to an idea behind a spec-fic novel I'm researching. What would the new world order look like and possible impacts be, given a relatively major catastrophe/crisis? Not pretty, whatever way you colour it.
The Hunger Games never really dealt outside of the Panem state because, quite frankly, it had little to do with the protag's conflict. Over-simplified, she's distracted by another priority: staying alive within the system. I never had an issue with the "limited focus" of Hunger Games in that aspect.