When we talk of ultimate success in A-stan, you are talking many, many decades. Maybe not even in our lifetimes. And nobody knows what it will look like. The one thing I know, is that the longer we pressure the Taliban, and the longer we (NATO) are a factor, is the longer they must shift their tactics to the point we create divisions of thinking, beyond those that are occurring within Pakistan. It isnt widely reported, but they are killing a steady stream of civilians.
To play off of that, will be much harder than it was in Iraq, because of the tribal society within A-stan. But over time, likely a long, long time, once we bring a more fairly modern lifestyle, history has shown, that the tribal influence diminishes.
So many educated people have written books on this, and Iraq. Sometimes, it plays out a lot more simply, than these people think.