No aircraft that has been hijacked since will have its passengers meekly sit subserviently as they fly to their doom.
But they are now unable to gain access to the Flight Deck - so they can do no more than the passengers on the Germanwings flight were able to do . . .
Likewise air forces on the ground will prevent any aircraft getting near built up areas.
Though eight minutes doesn't seem enough time to react and respond - was there any evidence that the Germanwings flight was being intercepted?
I agree that there was no built-up area near by, but if the FO had maintained altitude there would have been no trigger for ATC to decide on action.
Could the Captain have contacted 'base' from outside the FD?