How come after 10 years such an elite force like the Marines, can't defeat a bunch of Ragheads in Afganistan?

The Mujaheddin have no sophisticated weaponry, use crude tactics, have no strong logistics, posses scarce communications, own no money, fight with no armour, no air or navy support, crude intelligence gathering, and the list of qualities goes on and on. Is the USA really in a war? Or is it an excuse? For what?