That's a point, but frankly the wars were expensive because you have an organized, uniformed military that has to abide by UN regulations and the Geneva convent

That's a point, but frankly the wars were expensive because you have an organized, uniformed military that has to abide by UN regulations and the Geneva convention fighting people (guerilla units) that aren't held to any of those things. There's a cost to being legitimate and it's more than people would think.