Beamer and Bats you are both forgetting or disregarding the leaps and bounds intelligent software is making with regards to going through mountains of data both textual and visual.
The NSA is already basically "combing" the desert with regards to internet traffic both domestic and international, and DARPA is developing blimp drones that will be able to monitor hundreds of square miles of territory up to a resolution of a few centimeters.
Manpower is not key here, smart AI like software is. And that shit is pretty damn smart already.
I have a nifty blue line!