https://en.wikipedia.org/wiki/Peace_dividend
https://www.macrotrends.net/countries/USA/united-states/mili...
After 2001, military spending went way up of to fund the Global War on Terror. Most of that was a total waste and failure. Now the GWOT is essentially over and funding priorities have shifted to containing expansionist regimes in China and Russia (and to a lesser degree Iran) as part of Cold War 2. It is certainly an option to adopt an isolationist stance and cut the military-industrial complex down to the minimum size necessary to defend the homeland, but you might not enjoy the results of letting hostile foreign powers dominate the rest of the globe.