Ignoring the privacy concerns, we spend an awful lot of money on the NSA. Tens of billions for sure. Maybe if they'd been thwarting a 9/11 every week (or if we were at risk for a 9/11-scale event semi-frequently) I'd feel that we hadn't quite wasted that money.
The money isn't "lost"; what's gone forever are millions upon millions upon millions of man-hours that could have been used to do something useful. Saying the money is lost is just a handy shorthand for expressing what a waste it all was.
