I imagine all those folks living in those empires and dynasties believed they were witnessing the end of things also, just as we are today.
Nothing ended, it just changed. As it is now, it was then.
100 million Americans getting some or all of their living expenses from the government. This won’t end well.
It's different today. The US has armed those who want to destroy us, sometimes intentionally, sometimes from the sheer excess of weapons in dangerous places, and financed and trained our enemies. We've given our enemies a military as advanced as our own, and destabilized areas where they can grow.
It used to be when governments fell people lived daily lives, many after the horrors of war, but with more localized govs. Soldiers with their skills and weapons often stayed behind and were absorbed into the population. But the fallen areas rarely quickly became as much of a threat as the empire that fell.