But waiting till a single incident almost happens to scream "failure" while ignoring the fact that no additional airplanes have hit buildings since 2001, and then claiming simultaneously that the lull was do to nobody wanting to attack, and that our protection efforts are useless, seems hardly convincing.
The reason no airplanes have hit buildings since 2001 is because of the magic rock I bought on ebay back in 2001. It also prevents me from being eaten by lions, tigers, and gruffalo. I'll sell it to you, if you like.
I have a theory that it's impossible to prove anything, but I can't prove it.