Possibly already did, but the average citizen would never know it, world war will very likely never look like ww2 and ww1 again all due to MAD and the bomb. Instead we will be treated to unending proxy wars, more events like blood diamonds and an unending onslaught of misinformation or outright lies, all three of which the three superpowers are now professionals at in a digital world, all in the name of control.

Quite simply ww1 and ww2 were profitable, a similar type of war between the superpowers as they currently stand is not profitable for either side win or lose. What is profitable is selling arms to third world countries and ruthless despots, then arming their opposition for even more gun sales. What is profitable is uprooting a democratically elected leader in favor of a ruthless totalitarian because hes willing to sell his countrys future in the form of their natural resources. What is profitable is feeding the news media with so many blasphemously stupid headlines that any posturing done on the subject will bring reader/viewership and perpetuate the stranglehold advertising has over our minds by shoveling more shit at us to buy because it will keep us "safe"

War is commited for land, resource or profit, a war like ww2 between Russia China and the US in the current world leaves onoy decimated land, burned resources and nobody to trade goods with of any real consequence.