One problem no one wants to dwell on is that there is no one Afghanistan. Instead there are dozens of ancient entities that agreed several centuries ago to join a loose coalition called Afghanistan. This was mainly to deal with foreigners from outside the territory that encompassed Afghanistan. There were dozens of local traditions on how all the tribes within Afghanistan handled each other because someone from a different tribe was a foreigner and often considered a hostile one as well. The cities developed new cultures, influenced by foreign visitors and ideas. But even now most Afghans live in rural areas where local rules are more important than any decree issued by a provincial or national government. This reality explains a lot of things, like why the Taliban never controlled all of Afghanistan and none of the neighboring nations wanted to take control of Afghanistan either. With all the cultural and political divisions and not much of an internal transportation network there are better places to invest your money.
The lack of any history of a functioning national government is why, even before President Obama's two surges, I wanted to decentralize our objective:
The end result in Afghanistan, if all goes well, will be a nominal national government that controls the capital region and reigns but does not rule local tribes and which actually helps the locals a bit rather than sucking resources from the locals, who in turn do not make trouble for the central government or allow their areas to be used by jihadis to plan attacks on the West. We press for reasonable economic opportunities, with bribes all around (I mean, foreign aid), to keep a fragile peace.
And we stick around this time, unlike after the Soviets left Afghanistan when we ignored the place, for a generation or two to see if we can move Afghanistan into the 19th century (hey, let's not get ahead of ourselves).
I'm not sure if we are too focused on bolstering the paper national government of a geographic region called "Afghanistan" at the expense of the multiple ancient entities that will dominate Afghanistan once the massive foreign aid funneled through the central government removes the reason for the rural periphery to go along with the fiction of an Afghanistan nation.