Without an enemy there can be no war and no war profits, and no excuse to remain. The West is in Afghanistan to protect that oil pipeline, they cannot let the Taliban disappear.
This is no mistake.
http://hosted2.ap.org/IDMOS/e0478123c3cf489bb836130ffdbd2b5f/Article_2011-08-16-US-Afghanistan-Corruption/id-62e41f31647a4cd2b7d207b60f81b389