I don't see how that argument is justified. Maybe the Marshall Plan and the European Community saved Europe from war. Maybe Maybe globalization and general civilization-wide wealth creation made it so the elite's and xommonners businesses are less profitable in large scale war. (Note that even today, wars happen in poor countries, not rich countries). Maybe democratic evolution made the "send peasants to war" model obselete, and maybe modern communication made it harder to sell the fascist lies that motivated WWII. Nuclear Weapons didn't prevent Vietnam or Korea or the Middle East wars.