Been that way for all of recorded history and it follows the same trajectory as the various empires. Newly liberated slaves establish a close knit agrarian society, those which are virtuous have more success than their neighbors and a nation forms around this success. The nation expands, and soon has to fight more and more wars in order to keep up with the demands of a larger, resource consuming populace, until it is an empire... then the rot sets in.
Interesting post, your #5.