- the end of the cold war, with the clear hegemony of the US which halted state-sponsored terrorism from unaligned-but-socialist-minded countries (especially Libya)

- targeted assassination of terrorist leaders and infrastructures (no more training summer camps) no matter the country they are in (mostly through drones nowadays), leading to a progressive reduction in sophistication in terror attacks committed, and the rise of lone wolfs instead of structured terrorist commandos.

Now if you attempt to hijack a plane 100-300 passengers will beat your ASS and stop you before you get anywhere near control of the aircraft.

There will never be another hijacking attack where the pilot loses control of the plane from a threat of a would be hijacker.

(...But logically and intuitively everything I just said is extremely stupid because by that logic 12.01 counts as "dozens" and that's ridiculous, so your complaint is absolutely correct and I agree with you 100%)