Incorrect. Not talking about current and ongoing military operations and global presence. Speaking simply to funding a living stipend of a retired military person's life from the time they leave to the time they die at whatever age that is without putting anything back in whatever form that may be.
Since you brought up geo politics, let's dive in from a high level view. Up until WWII, the gobal economy was minimal with larger countries controlling regions of economic activity. Trade existed, but limited and many smaller players were kept suppressed. After WWII. the dominant presence of the US military opened up global trade through its presence of protecting shipping lanes.
It brought world wide stability for the most part keeping smaller aggressive gov'ts at bay from taking advantage of smaller yet important economies.
It opened up these specialized economies to do what they do best in return to get what they weren't as good at getting.
Anything else I should