Primitive or modern, any empire collapsed under the weight of it´s own greed, and under the cost of their own might.

There is a general opinion that he second world war experience should never happen again.

Unfortunately is just about to happen again, this time far uglier, it will be WWII ten times fold. Conventional weaponry is now in many more hands and far bigger quantities than it was then, various orientations groups, fractions, alliances, not all of them governments, many of them para governmental, supra governmental, and many, way to many in the mafia of all colors and orientations.

And the non-conventional weaponry, just in the same hands in enormous quantities.

What is happening right now in Syria, Ukraine, Mianmar (ex Burma) is just a picnic, an appetizer.

"The sky is falling."
not yet, but we laid the foundations for this pretty good for that to happen.

Sadly, if it gets to that point. It will end quickly. Millions will lose their lives. So sad. Our world will never be the same.

It wouldn't be the first time apparently.
It seems at least 10 other civilizations on earth reached the self destruction point before us, than someone came by and re started all over again, ours is pretty much 7 to 10 thousand years old only and already prone to self obliterations.

More and more empires are rasing on the bodycount of innocent people, out of the ashes of other dead empires, each time they get bigge, stronger and destroy more to hold to the power they clinged too by hoarding, killing and ruining regular people.

And they require resources to stay in power, and resources get stolen out of greed (by their oen people) so more people are needed to guard them resources, and more resources to pay those people, and more theft takes place, hence more people needed to guard these other resources... a self destructive game.