Even that is a false media narrative put up by the Dims during the early stages of the war to make the US military's goal a near impossible one (and to make Bush look unsuccessful). Look at all of the wars in history that successfully ended an aggressor nation's attacks without capturing or killing the head of state. Al Qaeda may not be a literal nation and Bin Laden a "head of state", but the principle still applies.
The only legitimate reason to go into Afghanistan was to kill as many people as it took for Afghanistan and/or the Taliban to surrender and for us to trumpet loudly to them and everybody else paying attention that attacking the U.S. is unhealthy. If I had my way we would have gone into Pakistan too, given how much we knew even then that Pakistan was as in bed with Al Qaeda as Afghanistan was.
That's how we went into war against Japan after they attacked us. That's why our part of WW2 didn't last forever. And that's why it was a loooonnnnnng time before someone else attacked us again.
Would agree with you if you were talking about Saudi Arabia.