We now define winning a war much differently than we used to. We now look at consequences and don’t call a war over until they’re known, we used to just look at the treaty. By the modern view we lost WWI because the mess we left behind gave us WWII. Heck given the way WWII put the pieces in place for the Cold War, Korea, and Viet Nam by the modern view we lost that one too.
We won the wars, but lost the peace.