Why wasn't bin laden taken prisoner?

Answer 1

The usual reason proffered is that the extraction team sent to Pakistan did so without the consent of the Pakistani government, which was believed to be complicit with his hiding there. As a result, the operation had to be performed on a short time frame and it is much easier to extract a dead person than a living one, i.e. subduing a person while keeping them alive is much harder than killing them.

Another secondary reason is that a long trial would likely increase sympathy for his cause during the length of his trial. We saw similar growth in sympathy during Saddam Hussein's trial and the trial of Zaccarias Moussaoui. This sympathy would help to crystallize Osama bin Laden as a martyr, which would be against US interest. A death away from the light is much harder to rally around than a slow drawn-out media show.