We had "won." A peace agreement was signed. Although that has nothing to do with your original argument that technology can't match "stone age" tactics. You can try and spin this into something higher about a country reneging on a peace agreement but that has nothing to do with your original argument. If we had the Taliban or Al Queda sign a peace agreement it wouldn't be worth the paper it was signed on. It would be like when Arafat agreed to cease hostilities on behalf of the PLO. Worthless.
Furthermore, we used guerrilla warfare in Vietnam, Iraq and Afghanistan. Still didn't work because like I said, those regions are unwinable because of their culture. Has nothing to do with a low tech vs high tech approach. That doesn't mean you don't fight those wars either. No one knows how an indigenous people will react to an invasion. Anyone who thinks they know, has been smoking something.