That's an interesting observation. I wonder whether a falling empire correlates to children misbehaving at schools.
I wonder whether studies were done on it in Britain or Spain, both of which you could say had empires which collapsed (though this did not threaten their whole existence).
To be clear, I'm not claiming that it does correlate... I'm only saying that you can't be sure it doesn't. It could be a selection effect, in that while it is said by everyone everywhere, we only hear from people in their cultural prime, which is just before the collapse. On the other hand, it may not be something everyone everywhere says, and it may be something that is mostly said by people in collapsing empires, in which case, it may very well be a true observation.
My main claim would just be that we don't have enough data to cite this quote (were it real) in mockery, as it is not quite as obviously wrong as it may seem from the very casual view of history.
I wonder whether studies were done on it in Britain or Spain, both of which you could say had empires which collapsed (though this did not threaten their whole existence).