US + Allies had clearly superior technological force, but still "lost" to some pretty irregular forces.
I don't think it is so black and white. If Russia/china/pick-your-bogey-man-of-choice invaded your country tomorrow with a robot army and started taking away your way of life (eradication of your native language, your native currency, your media, history, certain foods, schools etc), how do you think that would go down? You'd just roll over and accept everythingyou know and love about where you live being permanently removed because their robots were better? It is the same reason that we can't just have a game of chess to decide it all: when it comes down to trying to force someone to do something against their will, the ultimate and final fall back position is physical force and so sadly violence one way or another.