The type of operation carried out by our Navy SEALs to take out UBL was far more effective and far cheaper than fighting a massive land war with no discernible direction or visible endgame anymore. The other problem of course is that Afghanistan simply isn't interested in being anything other than a country run by sharia law. Outside of killing everyone there who is making that happen and making the place a US colony (something we quite honestly should have done in the beginning), how can we change this?
The second we allowed for Afghanistan's new constitution to be based on islam was the day we allowed for this outcome to occur. Unless we want to refight this, there's no turning back now.
You left out one more more piece...there’s all this mineral wealth, which some now believe that China is ready to walk in...sign business deals and more or less get a free ride from US security.