> It led to a generational mental model of inevitable decline, or of cycles.
No, it didn't. That model of decline or cycle describes essentially every cultural viewpoint--the view of an inevitably inclining state of humanity is quite rare, and I'm not aware of anyone advancing that before the rise of humanism. It predates not only the fall of the Roman Empire, but the rise of the Roman Republic before it, probably predating even the Greek and other civilizations that arose out of the Bronze Age collapse.
Medieval civilization did live amongst the ruins of the earlier Roman civilization, but their experience did not originate the idea that humanity lives after the end of a golden age.
No, it didn't. That model of decline or cycle describes essentially every cultural viewpoint--the view of an inevitably inclining state of humanity is quite rare, and I'm not aware of anyone advancing that before the rise of humanism. It predates not only the fall of the Roman Empire, but the rise of the Roman Republic before it, probably predating even the Greek and other civilizations that arose out of the Bronze Age collapse.
Medieval civilization did live amongst the ruins of the earlier Roman civilization, but their experience did not originate the idea that humanity lives after the end of a golden age.