Assyrian Empire. No chocolate. Conquered.
Babylonian Empire. No chocolate. Conquered.
Carthaginian Empire. No chocolate. Conquered.
Roman Empire. No chocolate. Fell.
Mongol Empire. No chocolate. Disintegrated.
Without chocolate, we are doomed.
That's good enough for me! And it explains why there aren't any alien civilizations knocking on our doors. They ran out...of chocolate...(shudders)
But don’t forget the chocolated Aztecs. The Spaniards did a combination of wiping them out and diluting them. After all, even chocolate is not worth killing men on top of pyramids.