[Insanity]

'advanced culture' is in the eye of the beholder. At the time, Rome was an advanced culture and we have a bunch of details of their fall.

Not to take away from your point - I agree and the current fall makes it more tangible.

[PaulHoule]

The fall of Rome also took centuries, historians can't even agree on exactly when it began.

[Insanity]

True for the empire, not true for the republic (which still took decades but not centuries)

[nephihaha]

In the case of Rome, it depends how you define "fall". There were certainly some military setbacks and also some bad climatic conditions (which affected central America and China around the same time.) Probably better to say that Rome was in decline for a long time.