I wonder why?
We were not a major player until WW1.
And even then, we downsized our military afterwards.
It was not until after WW2, that we didn't downsize our military ... and began using it to intimidate developed nations.
Prior to that, we used "gunboat diplomacy" on "banana republics" and nations lagging in military technology.
And only after WW2 did we worry about outpacing other nations in military development - so we could intimidate them.
Prior to WW1, we were a bit player on the world stage.
After WW2, we became a leading actor.