Errr... how exactly are US troops reaching Afghanistan? I don't think the Pakistanese government would help the USA without the outrage caused by 11-S, and the other possible routes are: through Iran, China, or a combination: Georgia, Azerbaijan and Turkmenistan.
NATO members can still support the invasion and send troops, of course, but without 11-S they have no obligation whatsoever.
Finally, if with troops in the ground, the USA has failed for almost eight years to kill, let alone capture alive, Bin Laden, what allows them to get him within days with no support inside Afghanistan?