Can you show any time FAM made a difference, or the unopenable doors prevented another attack?
All I can think of is the Germanwings flight where the door basically caused the crash.
Times have changed. Terrorists have moved on. This idea is a few decades late, and relatively useless now.
People are also less passive now. They are less likely to stand by scared of people with boxcutter, as they have already stood up to people with guns (even when they don't have any themselves).
I think you advocate a society in which the government is the sole keeper of peace and security. The government is no longer viewed with the same benevolence as before, especially after Wikileaks and all the other stuff showing how the government spies on its owns. Many people have lost trust in the government, with partisanship becoming more vicious and officials seemingly not caring what happens to the common person, as long as they "win" (whatever they means).
And the government policing itself? I doubt any intelligent American believes that anymore.