For a time I led a UN project office in Afghanistan. The oldest and wisest white-haired Afghan once told me "We'll always need an international to lead us, other wise we will fight among ourselves." Sure enough, several years after I left an Afghan stayed a coup, driving out the internationals, leading to corruption and the eventual dismantling of the organization.
Keep in mind that the present predicament of the US goes back to the British, who deliberately created national borders that split the Pashtuns between Afghanistan and Pakistan, and hobbled together opposing ethnicities to cause strife and weakness. The US could have begun fixing this problem by splitting Afghanistan in multiple nations, however, it's also easier for the US to exercise influence over a piecemeal weak nation, than several stronger nations of unified ethnicity.
Afghanistan pre-existed the Brits. The reason Pashtuns are split between Afghanistan and Pakistan is because the Brits never mustered the force to both overrun and administer the place. They overran local forces several times, but it was an expensive proposition to garrison the place and there was not enough government revenue from trade to justify placing a large permanent force there. Afghans will give you all kinds of conspiracy theories, but they are given to conspiracy theories. The reality is - way before the Brits showed up - the Pashtuns built an unwieldy empire of Tajiks, Pashtuns, Uzbeks and Hazaras but can't control it because they've repeatedly run into the same problem as the Brits - the country is composed of vast swathes of wasteland that can't provide enough revenues to keep the empire together.
You can’t civilize tribes. Africa is proof.