Here's something that actually reinforces your point, but I'll explain why this happened.
U.S. Concludes Bin Laden Escaped at Tora Bora Fight (washingtonpost.com)
He slipped through out fingers. I've written up a few things on the constraints and ridiculous rules that we have in the military and why we can't operate effectively. This is one example of what happens because of lame rules. On top of that, we were still somewhat new to this and depending on not only the AMF (Afghan Military Forces) but our other coalition partners. The coalition I can honestly say has done a wonderful job in Afghanistan. The AMF is what the problem was. We tried to let the Afghanis conduct the majority of the fighting at Tora Bora. We learned since then that they have to be escorted, watched and trusted only so far. You'll find pockets of TB sympathizers anywhere and everywhere in Afganistan, and it only takes one who knows the plan to screw everything up by telling the enemy what that plan is.
So if you wonder why our numbers were so low at first in Afghanistan, it's because we didn't think we needed bigger numbers. We had the coalition and we were training up the ANA (Afghan National Army) to do the job for themselves. We didn't want to become an occupying force, policing the nation; we wanted the Afghans to do it for themselves. Our intent was to give them the assistance they needed to accomplish that and get out. But that task turned out to be too much for them to handle, and foreign fighters flooded into Afghanistan for their chance to join in the jihad.
In a nutshell, it's not that we didn't want to capture Osama. We underestimated everything at first, and that cost us our chance at capturing him. We've learned since then, so I doubt it will happen again.