The whole idea was to empower the steppe peoples -- Turkoman, Kazbek, Uzbek, Tadjiks, whatever -- who were in Gen. Dostum's army and in Ahmad Shah Massoud's mujahedeen army (these were the guys who really threw out the Soviets -- the Taliban came along later) against the Pathans and their international Salafist Al Q'aeda allies.
The Taliban were Pushtu-speaking Pathan and western Pakistani madrassa products from across the mountains, and it was their hosting and providing a nation-state rabat (R&R, training-up, and rear-echelon area) to the international Al Q'aedist terrorists that added up to casus belli between the United States and the Taliban's deemed government of Afghanistan.
Without Taliban/Afghan government support, Al Q'aeda could not have put together the 9/11 attacks in the West, the embassy attacks in Africa, the Bali bombing, and the USS Cole bombing -- or the Khobar Towers attack in 1996 that preceded all these other attacks (20,000 lbs of ANFO in a gasoline tanker, four times the size of the OKC bomb).
That's why we're there -- to extinguish Pathan political and military power and their ability to reinforce across the Khyber Pass. Something that the 'Rats are very busy trying to get the American People to forget, like Svengali hypnotizing one of his subjects, or the NEA maleducating one of theirs.