The anti-Soviet mujahideen of the 1980s morphing into Taliban and Al Qaeda in the 1990s and now mutating into the virulent ISIS becomes possible when there is a continued demand for their lethal product. Pakistan's consistent use of jihadism as a tool of statecraft and foreign policy over the past four decades has created a jihadist ecosystem which would require much more than tactical measures like the military operations it has undertaken so far.
If the United States and NATO forces withdraw from Afghanistan, it is very likely that Russia will return to its traditional role as the Afghan government's principal sponsor. Already, the Kabul government has asked Moscow for additional military aid and Moscow has agreed to sell Afghanistan an unknown number of Mi-35 attack helicopters.
While relatively few Afghans are anxious to see the Taliban's return, many seem willing to believe their promises to govern differently than in the past. Incidents like the strike on Kunduz's Doctors Without Borders hospital by American gunships can also serve to channel anger against a Kabul regime reliant on foreign troops.