As ridiculous as it may sound, I fell Taliban will be exactly that. Taliban are the last people to expect sanity from, yet they are the ones who will be sane, mark my words. It's early days and the present hardship will pass. After two misadventures by two superpowers I don't think any other power has any desire of adventure in Afghanistan in a long time, so there will be peace for a long time. I also have another less than rational hunch, the Afghans were a ruling race for many centuries in that region and in India too. They may have found themselves backward in the 20th and 21st century but I don't think their national/racial traits of being rulers have vanished. 20/30 years on, it is to be seen between Pakistan and Afghanistan who turns out to be the dominant one.