The purpose of our mission there was, is and still should be to stop more 09/11s coming out of Taliban controlled Afghanistan by killing people who aim to kill Americans with mass attacks like 09/11 was. That mission has been an unmitigated success for 20 years. It's a mission tailored for SOF, because that's what they do, and can continue to do as long as there is a threat there. This is not a war, it's confrontational threat short of war.
We don't need to involve our conventional Forces other than small level of strategic bombing in support of SOF on the ground.
As for the naive and idiotic objective to make Afghanistan a democratic ally, that fool's errand needed to be scrapped as both a mission and as a propaganda program long ago.
We pay those Afghans who help us kill enemies, and that is as far as it goes. History tells us that the Afghans cannot be changed or organized in a western sense. They will never be more than a tribal people who like killing each other and foreigners. Their state of being has nothing to do with America's vital interests in any event. Who cares?
But tragically both US parties stupidly misunderstand our purpose and limitations of intent, and have made stupid reductions to remove our protective SOF shield there. Thus our vulnerability to yet another successful strategic strike against our Homeland , possibly nuclear, from a radical Islamic element based in Taliban - controlled Afghanistan has increased significantly.
Dumber than dirt.