Probably because of what goes on behind the media's lenses.
What we know about the war on terror is what the government has told us so far. Hell, there have been things all throughout history that the government has withheld from the public that are involved with it's warfighting strategy. You think half the crap we know about what went on in the Cold War was available information to the general public?
How many spies do we have in Al Qaeda?
How many informants have infiltrated mosques?
How many terror attacks have been thwarted without us even being told?
What kind of techniques have we truly used to extract information from detainees?
The devil knows what kind of illegal tactics the CIA has used on terrorism suspects.
No one is sure. And it's a pretty good idea for counter-terrorism agents to not leak their warfighting strategies.
We won't know for decades. This is going to be a long war. Al Qaeda ideology is found on every continent with facilitators worldwide and a huge web of those who are sympathetic towards Al Qaeda, but would not actively engage in terrorism.
One of the worst consequences of the war on terror is that if we've been fighting it so effectively and hiding the same strategies we've been using, the public will begin to think that terrorism is simply a huge hoax like so many conspiracy theorists do.
The truth is we just don't know what's been going on behind the scenes.