When reading comments like these, I can't help but wonder what the public response would have been if the government had taken action against a vague hijacking threat in Aug-Nov of 2001.
Pre-9/11, hijackings meant you sit tight, land somewhere, and most of the folks probably walk away OK. Even an unarmed person could hijack a plane with the claim of concealed explosives or weapons.
Post-9/11, we have reinforced cockpit doors (the effectiveness of which were sadly demonstrated by Germanwings flight 9525) and passengers who know a successful hijacking probably means dying. Even on 9/11 itself we saw the impact of this - flight 93 wound up crashing in a field because the passengers knew there was nothing to lose by rising up.
And that's exactly what the gp is talking about.
I actually used to think the same way, until I mentioned how silly some of these security theatre steps seem within earshot of someone who did some kind of Federal security work.
He went through a long winded explain of all the steps that it would to make a switch to circumvent one restriction, how much time it would take, and how it would only take one suspicious interaction by one of the group members for something to be reported.
Basically, while you can't protect against everything, by making attacks an order of magnitude harder (going from blades to bombs), you greatly increase their chances of being discovered.
You wrote that as fact, but is it? Those "highly trained" guys could barely fly a small plane, but where able to fly huge airlines at top speed.
Most terror attack in western countries where commited by lone wolves or tiny groups. 9/11 was incredibly well-thougth in comparison.
America prior to 9/11 really seems like a different world. Social media was in its infancy, and 24/7 news channels hadn't kicked into overdrive (I don't even think scrolling tickers was a thing yet, outside of financial channels). By spring 2001 there was obviously political angst about the election and Florida's role in it, but both sides of the political spectrum weren't fueled by the constant outrage machines they are today.