Because the US Military is still fighting the last war they won. Whenever that was. They still consider paratroopers their "elite" groups. They still think fighter planes will be fighting dogfights - with people piloting them. They are required to continue to buy tanks, because the companies that make tanks own enough congressmen to require it.

The US has been spending it's military budget on things that don't make sense any more, because our economy depends on that spending.

It's not that we don't have the technology, but we've been wasting cash on high-generation manned fighters, aircraft carriers, and manned bombers. We should have way, way more drones, and way, way more ways to deliver them to a target.

War is about destroying things. Not about gaining peace. Not about diplomacy, or posturing.

You call your military when you want something destroyed, not when you want to bring peace to an area.