Well part of that is that what we consider "Roman" culture and history is actually the culture and history of hundreds of societies that the Romans became admin

Well part of that is that what we consider "Roman" culture and history is actually the culture and history of hundreds of societies that the Romans became administrators of. That's one reason why there were so many places like Austria, Romania, Byzantium, and Catalonia that claimed to be Roman successor states. It could be argued that true Roman history ended in 90BCE and from that point on it became more "Classical Imperial Europe" history because their administration had become so massive and encompassing. So much of that supposedly Roman history details the people of Iberia, Asia Minor, North Africa, and the Rhineland. Through their own biased lens they were really historians of the cultures they turned into protectorates.