Yeh Afghanistan can be better controlled from outside, just like ISI/CIA did for decades, .. well Pakistan treat Afghanistan as 5th province, maybe still 
So please take your this so-called pride of graveyard of empires somewhere else, it was super power vs super power. Even still .. we all know why American-led NATO forces having troubles, some countries come to mind:
Pakistan,
Iran,
Saudi Arabia,
China,
Russia.
I will buy your word, when Afghani’s single handley take care of Pakistan let alone USA 
.. ..