Funny

The Hunger Games owes everything to Stephen King. They basically just took The Long Walk novel and glittered/mashed it up with The Running Man movie. Neither of those took place during or after any apocalypse. They were each just set in either the now, or the very near future, in an America that has gone fully corrupt as a result of being morally, politically, and economically bankrupt. King was (and always has) written very local and topical stories set in what is literally his here and now. When he lived in Maine, he wrote Maine stories. When he moved to Florida, he wrote Duma Key. So, it's no surprise that a YA story as derivative as The Hunger Games would have the same blind spot for Global events as the inspirational works.

But, also if we were really going to descend into an apocalypse (or a dictatorship), news of the broader globe would be one of the first casualties. People inside most apocalypse (and fascist dystopian) stories don't usually have a lot of knowledge about the "outside" world. If they do, it's usually an unreliable narrative.