Armies trained by the US are curiously notoriously weak and inept. South Vietnam, Afghanistan, Nigeria, and Iraq are examples. A weak state is no threat to the US and guarantees more wars. Our war pigs financially prosper from such deliberate nation weakening. Their toadies in DC use war to strengthen their power bases. And of course everyone makes money when the US gallantly helps to rebuild a country after it’s been mostly destroyed. The country takes on huge debt, making banksters happy, to finance construction done by mega-companies, and money then flows to politician’s re-election funds. Is everyone happy? You bet.
At the risk of sounding conspiracist, I can’t help but suspect that perhaps this is deliberate. Making sure other countries have weak armies keeps them dependent on the US. What’s more, it means their armies can never pose a threat to the US. (The logic here is not unlike that of Trotskyist and Maoist sects, which keep their front groups weak, so they can never pose a threat to them.)
It could also be that despite our tedious strutting at how marvelously exceptional we are, that our military just isn’t that competent or that we blunder into countries with no actual plans, alienate the locals, then are baffled when things turn into another yet quagmire that no one could have possibly predicted.