Allowed?
bin Laden at least has a $25 million price on his head. It's hard to see, if there were an opportunity, some opportunistic Northern Alliance or Pakistani passing over that much money. Retire to Beverly Hills under a new identity and partake of the fruits of American capitalism.
I count it more likely that he is dead under a pile of rubble in one of the bombed caves, or smuggled out of the country incognito by people loyal to him (and who know he can pay them as much as the bounty). Not that we "allowed" him to escape.
