A city being abandoned has gotta be a significant event or period to live through. Even something like a palace being destroyed and not rebuilt would surely be notable.
Was it in the way of realizing civilization as they knew it was collapsing though? Detroit has been going through the process of abandonment since the 1970s. Civilization doesn't seem to be collapsing though, just the one city as people move abandon it. (though of course that might be my perspective, history will tell if that is the early sign of the collapse of our civilization of the next few hundred years, or just a minor blip.
Rome was the capital but it wasn't the civilization.
People experienced war all the time back then. The idea that most had any idea what was going on in any deeper lever flies in the face of at least how I understand history.