In my opinion, your comparison of OBL to John Brown makes sense.
After Hitler died, the Nazi movement (cult, if you will) fell apart. The Nazis not only lost their leader, they were thoroughly defeated on the battlefield.
It’s not the same with AQ. New leaders will emerge as long as victory seems possible.
This is going to be a long epic battle. They plan to come here civilly and start Sharia. 100 years from now, our children’s children and children’s children will fighting this battle right here on our streets.
The real battle will be one with spiritual education and with the reality that the 5th Column is strong here.