I would argue that the Taliban was different - a guerrilla battle (similar to Vietnam - which we also lost) rather than a direct conflict. I believe that the US, while not very good at the former, is still among the best at the latter - although I would rather not find that out through direct experience...
> similar to Vietnam - which we also lost
Vietnam wasn't lost militarily. It was lost politically due to the war's unpopularity.
If America had been able to win it quickly, then wouldn't the unpopularity not have mattered?