The primitive societies, such as bands and tribes, are in states of constant war because they have no official governments to establish peace. As societies grow, more organized classes emerge, such as religious leaders, who incite sacrifices and holy wars, and political leaders, who incite raids and proper armies. Eventually such lower societies connect into proper nations, after they have warred enough with each other that they’d rather all war together against somebody else’s nation, or several other nations, on behalf of whatever is available.
A society is really only proper once it develops sea and air travel, and can thus fight primarily one-sided wars against lesser societies, until they are subjugated to the point of noble objectification and abuse. Then, you see, then society flourishes, and you get intellectual endeavors like “world wars,” or “world wide webs,” on which whole new societies develop and war by taking each other’s sites down. They invent realms in which to war.
That’s the real difference between primitive societies and developed ones: the primitives are always at only one war. A developed society can lose many wars, all at the same time.