This is the problem.
To discuss this, there's too damn much mythology that has to be carted off first. Afghanistan is not Iraq. The logistics are a nightmare for a ground war, the country is bigger and far more rugged, and the population is larger and much less civilized.
Go back and look at the invasion of Iraq. In Afghanistan, that kind of ground attack with its associated supply lines, would have been completely impossible. Even now, the logistics are a bitch.