If Bin Laden used Tor he would have been killed much more quickly. I feel bad for the person in a remote Pakistani village who is connecting to Tor, I am pretty sure that would have been enough intelligence to warrant further investigation. From what I have heard, it sounds like Osama had a human courier who took USB dongles with messages on them from him, then sent the messages quickly from random access points, and also got replies and brought the messages back on USB dongle. It doesn't even sound like he was using encryption or steganography from the reports, but I find this hard to believe personally. He was located because they tortured someone into giving up the name of his human courier and then they identified his couriers location and covertly followed him to the compound.