So? how about a fallout game that is just about surviving. It would take place over about 30 years and you would see how the united states changed after the bombs fell.
It's a different kind of game...a total survival game, and probably a "me against the world" type thing. Nothing wrong with that, but it's not the kind o setting that supports, as I said previously, factions, quests, politics, and Heroic Myth. It's difficult to see how a single individual could really accomplish anything that would impact the world.
I'd say start 20 years after the fall, at which time some social structure would be present.