Hello!
I agree that it is a nice idea.
However, I don't think you need a basic change like a pre-history. Look at terran history. For instance, there is ancient Greece, some of which sites are subject to archeology. The growth and fall of a civilization like Greece is basically already part of the possibilities of World Gen. (I recall having a world a few versions back, where a human civ had been completely whiped out by wars, I think with elves, leaving ruined cities connected with roads)
The things needed to reach greater archeology would be a greater diversity in sites during world gen (like extended caverns, underground cities) for all races, so that they are not stuck with a single pattern. And a greater flux for civilizations. That is, to have the possibility to have new civilizations develop. For instance, a prophet (probably a vampire or demon) could visit a distant hamlet of a civ and convert the people there to a new faith/attitude, thus starting a new civ. Or a band of bandits could gain control of ever larger portions of land, until they in themselves become a realm and thus a civ. This way, we could have more room for disrupted lines and abandoned settlements.
Factors for abandonment could certainly be different events like plagues, droughts, invasions. This latter point can be especially interesting for unfortified settlements. As a horde of hostile invaders conquer a nearby city, the surrounding villages may be abandoned as the villagers flee to the next city to seek safety behind its walls. But change can also come via commerce. If a city gets a trade connection with an interesting, new trade partner, it is likely to develop a certain pull that may drain other parts of the realm, maybe even to the point of abandonment. Likewise, if a trade partner vanishes or changes the trade route, a former booming city may turn into ruins and disappear under the sands of time.
Yours,
Deathworks