I (hold your breath) believe that the US is partly responsible for the problems in Afghanistan to begin with. The CIA provided the Mujahideen with the tech and support to defeat the Soviets - in particular the stinger missile. when the Soviets tucked tail and ran, so too did the US influence, leaving local warlords, etc to scramble for power. No doubts loyalties were questioned all around (who sided with who)...blah blah blah...but it is very arguable that Afghanistan is the mess it is in part because of a previous power vacuum.
On the flip side, even with US and coalition forces in Afghanistan it is arguably a mess. Experts on Afghanistan point to the extremely tribal nature of the country, coupled with a culture that is not enamored with (and therefore not in need of) Western technology and lifestlye.
So....if there a real difference between the chaos of the power vacuum versus the chaos of the US invasion forces attempting to keep order? Not really...
the idea of including the Taliban is a naive notion - they don't want to be included. they are culturally opposed to being "included" in some solution forced upon them be "Christian" western powers, and thus the solution will not hold.
As it is in Iraq, where there is a desire by many for peace, the religious/cultural bias against the western influence is such that there will not be a peace even if a "stable" government and military is installed. Of course...you could argue that in parts of Los Angeles, Detroit, New york, Miami there is no peace, either because of cultural and political differences...It may be that a certain amount of violence and unrest is simply a part of the human condition in these areas...