Hunting/gathering/swiddening tribes may have wars but they're just tribal wars, which are more like random murders. Lots of regret but those left alive can move on. In order to get awful generation-destroying authoritarian war wars, you have to have a sovereign. A sovereign requires what James C. Scott has called "legible" surplus. This is a surplus the sovereign can expect at regular intervals in the same locations. That is, fixed agriculture, preferably of grains or similar crops that don't spoil easily but require lots of related industry in order to support life.
Farming first leads to food surplus, but also to a food supply that occasionally collapses without alternatives. It also leads to large hierarchical society structures and problems around ownership of land/resources, which basically is what war is about.