One thing that I from time to time attempted to write on, albeit extremely poorly, was what kind of societies may form from the ashes and how it would advance given the example of a industrial, world-spanning civilization/economic system before them.  And when I say this I mean a fully fledged societies with their own cultures, languages and set of traditions (all of which having signs from the society we lived in today, but highly distorted in the teeth of time) be it akin to Greece or China, not warlords and successor states.

Like a civilization a millennium into the future after things go downhill in 2060 or so and just keep tumbling for another 70-100 years. 

Anyone know any post apoc settings go with that sort of "collapse" where things just keep getting shittier until society has been reduced back to tribalism and warlordism not from one traumatic event, but from a procession of progressively more destabilizing and disastrous events until everything just ceases not in a boom, but a whimper?