The Taliban are less likely to try and operate in large numbers (a few hundred troops) after they got banged up doing so last year. American reconnaissance and air power are too powerful for large groups of Taliban to succeed. But the Taliban can still terrorize their fellow Afghans into not cooperating with reconstruction projects, and foreigners in general. If the foreigners could be driven out, the Taliban factions could try and convince the tribal chiefs to help restore the Taliban to power locally, and eventually throughout the nation. That would be a very long shot, and the new PRT strategy is an attempt to prevent the Taliban from getting any traction at all.
And then there are the warlords. Most of the country is still run by warlords, and many of them meet their payroll via drug (opium and heroin) profits. The warlords fear no one, except American military power. They have seen what the Special Forces and smart bombs can do and don't want to be on the receiving end of this. Unlike the Russians, there is no way for the Afghans to deal with the Special Forces and smart bombs. Even during the 1980s, the Russian equivalent of the Special Forces (the Spetsnaz) were unbeatable by the Afghan warriors. But the Russians didn't have the smart bombs. So the warlords are willing to play politics and make the best deals they can. The central Afghan government now has a new constitution and upcoming national elections. So, despite the warlord armies, the huge drug trade (drug crop acreage has doubled in the past year, Afghanistan is the world's largest source of heroin) and Taliban trying to make a comeback, most Afghans want to give peace, and a national government, a chance.
The 10,000 Americans will stay, at least until Osama bin Laden and the senior Taliban leaders are caught. NATO has 5,000 troops in the country, and has promised to send more to provide armed support for PRTs throughout the country. Unfortunately, the NATO countries are not eager to send more troops to Afghanistan, as it is expensive, risky, and helps the Americans (many NATO countries are still ticked off at the way the United States removed Saddam Hussein from power.) The Afghan government wants 30,000 NATO peacekeepers, but would be happy to see another 5,000.
American strategy in Afghanistan has changed. Fewer combat troops will be "trolling for Taliban" (patrolling the border areas where Taliban groups are known to operate) and most of them will be supporting the eight new PRTs (Provincial Reconstruction Teams) being deployed by next month. That will make twelve altogether. Each PRT has several dozen civil affairs specialists, but not much combat power. The American infantry companies and platoons will provide security against Taliban attempts to stop reconstruction. The PRTs both see to it that actual reconstruction is done, and work to build up good relations with the local Afghans and their leaders. This, as past experience has shown, eventually leads to tips from Afghans about who is Taliban and who isn't. Do favors for Afghans and eventually they will do one for you. The American Special Forces have long known that this strategy would work, but never had the manpower or resources (cash) to carry it out on a large scale.