Wars will always be fought as long as there are politics and something worth fighting other such as food, water, oil, land, old hatreds, etc. Most conventional wars only last a few days. Many blitzkriegs. Also the fact that many modern armies are smaller, and most warstocks only last a few days. Either a stalemate happens, the war devolves into a long drawn out guerilla war, or someone will be occupied in a few days.