Everything the other guy said, but let me add: Taliban rule wasn’t as unchallenged as it is now before the US invasion of Afghanistan. They still controlled most of the territory, but a good part of it was also controlled by the Northern Alliance who were still fighting the Taliban. The current strength of the Taliban in Afghanistan is a direct result of the US invasion.
Everything the other guy said, but let me add: Taliban rule wasn’t as unchallenged as it is now before the US invasion of Afghanistan. They still controlled most of the territory, but a good part of it was also controlled by the Northern Alliance who were still fighting the Taliban. The current strength of the Taliban in Afghanistan is a direct result of the US invasion.