The problem I see is that war is a very natural element of civilization that regularly relives population stress. It's been a part of human society likely befor

The problem I see is that war is a very natural element of civilization that regularly relives population stress. It's been a part of human society likely before we even left the trees. It's simply not natural to go for many generations without a significant culling of your male population. I think it's not so much that humans haven't evolved since WWII, but that society hasn't evolved any kind of new pressure release valve.