So we should stay there forever?
Until there are no more Taliban. America is still in Germany, although the Soviets are long gone. The war criminals were tried and punished, at least nominally in most cases, with death or life in the slammer for the big boys. With the Talibani, also big league war criminals, you make a deal? Why didn’t you make deals with Himmler, then?
You invade Afghanistan, you have to leave it better than when you came. Otherwise, it won’t be over. In 1973, they had a civil, somewhat modern society and a constitutional monarchy. That’s up to them to reestablish, but they can’t if the Taliban’s able to terrorize the populace as before.