>>24516164
>Officially to get Osama
No, that wasn't the primary goal at all. Their stated goal was to destroy the governing apparatus (i.e. the Taliban) of Afghanistan because it actively sponsored and provided refuge for jihadists.
>Unofficially it was probably a huge mess of colliding interests
The war was prolonged because a) it was constrained (like what you see in Russia v. Ukraine) and b) the military industrial complex immensely benefited from it (i.e. there was no incentive to end the war).

So, did the US fail in Afghanistan? Well, Al Qaeda has pretty much been eradicated as a threat and it's unlikely the Taliban in its present form will sponsor or shelter Jihadists. Basically, the US dragged the war on and on until geopolitical conditions had changed to such an extent that Afghanistan was no longer an important focal point for global jihadists. Same deal with Vietnam--after the cracks in the Sino-Soviet alliance became obvious there was no more reason to waste resources toward containment.

Wars very rarely have a clear endpoint, anon. The vast majority of conflicts aren't the Napoleonic Wars or the World Wars.