I think you are confused. What the 911 hijacking ended is the practice of hijacking airplanes and taking them somewhere to negotiate for the release of the passengers. Ever since 911 it has been assumed that a hijacking will be a suicide attempt. The fact that no one instantly got up to jump on a bomb doesn’t change that.
What I am referring to is the macho comments on these hijacking threads about how Americans are rough & tough and would leap into action to subdue any terrorist. That apparently did not happen. According to news reports it was left to a Dutchman, no less, to leap over several seats to subdue the terrorist while his American seatmates yelled for someone to help.