The two real-life World Wars destroyed the pre-war order, despite involving a fraction of the death toll you believe is necessary to do such a thing. Several empires fell; the nation-state gained full supremacy; new countries formed, and others ceased to be; the balance of power shifted strongly in favor of the US; a global order focused on cooperation and economic integration developed; etc. The world as we currently know and understand it is a direct outgrowth of those wars, and would look very different had they not happened.

Yes, proper context is important, but I think you're overestimating the size and nature of a world-changing conflict.