While the organized state can certainly inflict large-scale destruction, such is not its aim. The state is meant to ensure peace, at least within its borders. They may wage war outside their borders from time to time. However, as nations have become larger and more stable, these wars have decreased in scope and number.
No one fights wars in or over stable countries. It's only countries with internal conflicts that invite wars, or countries that are relatively new and are looking to establish themselves. Look at it this way - Afghanistan, Korea, Vietnam, etc. - almost all post WW2 conflicts have taken place in or over countries that were not in existence prior to WW2 or were experiencing internal conflicts that brought in one of the major powers.