>The term "security theater" itself is often thrown around to criticize when it's completely undeserved. Lots of people use it to poke fun at the TSA, but the term totally dismisses the fact that hijackings have plummeted [1,2]. The TSA does its job.

Your graphic shows 'worldwide' data rather than US data. How would the TSA be involved in reducing hijackings on flights outside of the US? The connection seems spurious at best.

We could just as easily argue that hijackings correlate with other violent crime and the reduction in violent crime worldwide has led to their decline. Or that increased prosperity worldwide mitigates hijackings. There's very little basis to believe that TSA has anything to do with it.