But if there's ever another hijacking, it will end in one of two ways.
If there are FAMs on board, they will subdue the hijackers with deadly
force if necessary. If there are no FAMs on board, the passengers
will subdue them with deadly force whether it's necessary or not.

There is a third way for the incident to end - the hijacker succeeds! There
is no guarantee that a FAM would do the business.

Some of them would be too drunk on the free booze in Business class (They
wont be travelling economy) and not take the job seriously like the drunk
TSA chief at Dulles.

Good way to build confidence in the security arrangements.