Largely the US isn't losing control, it's giving it up willingly. For what reason, no one knows yet.
It was dragged into the first world war (despite strong public aversion) because J.P. Morgan Jr started lending money to Britain and France to buy American steel, thus setting in motion a cycle of investment and production protection that eventually required boots on the ground.
It was dragged into the second world war by Japan's attack on Pearl Harbor (and Germany's subsequent declaration of war, as it was obligated to do under its treaty with Japan).
It protected Europe and SE Asia in the post-war years in order to contain communism, which it feared more than anything else. Once that threat subsided, there wasn't much reason for it to continue with its overseas footprint other than inertia and protecting important trade routes.
Gulf Wars I was to protect oil prices (and because they already had the equipment for war), and Gulf Wars II was to be seen to be doing something about 9/11.
Now that Trump is in power, America is performing its "great reset" (which was going to come eventually), where it becomes isolationist again, sticking to the Americas (reinvigorating the Monroe Doctrine), and leaving everyone else to their own devices.