I am going to go off-topic for a moment. You probably heard that 6 Americans were killed today in Afghanistan. Their families are not going to have a Merry Christmas. They are going to have a painful Christmas.
It should be clear to everyone that this is not going to end until the US and all other foreign occupiers get out of that country. It is going to be exactly the same as Vietnam. That war went on and on and on, and despite a grossly lopsided death count in our favor (where we were killing a lot more of them than they were killing of us) the only thing that brought the killing to an end was us getting out. Once we and our puppets were gone, the country settled into peace, and it has been at peace ever since.
The Taliban fighters are never going to quit, and if necessary, the fighting will be passed on to the next generation and the generation after that. If we stay, and if we continue propping up our puppet government, then the war will continue indefinitely- and that is guaranteed. Ultimately, it will end with us getting out, and the Afghans sorting it out for themselves. The only question is: how many more will have to die before it comes to that?
Why stay? To save face? To avoid admitting defeat? Again: think Vietnam.