James Lileks as usual says it better than anyone:
It seemed right away like it would be a big war, three to four years – Afghanistan first, of course, then Iraq, then Iran. The idea that it would have stalled and ended up in diffuse oblique arguments about political timetables would have been immensely depressing. There was a model for this sort of thing, a template. Advance. But that requires cultural confidence, a loose agreement on the goals, the rationale, the nature of the enemy and the endgame. We don’t have those things. Imagine telling someone six years ago Iran would be allowed, by default, to make nuclear weapons. They would wonder what the hell we’d done with half a decade, plus change. What part of 25 years of Death to America didn’t we get, exactly?"