True enough. Cost for a trained dog starts at about $20k. And they have to be trained just about every day by an expert handler for at least an hour or they revert to a very expensive pet.
For the purposes of comparison, how much does a bomb-sniffing human cost?
$20K would be an excellent investment if it stopped one bomber intent on blowing up a subway car.
In strictly monetary terms, the U.S. Gov. considers the life of one person @ $250K. The ave. deaths /subway bomb in London was 15. That's $3.75 million per., not including material damage, general psychological damage and economic damage, locally and nationally. Then there is the emotional damage to survivors and friends.
So, investing several million in a bunch of smart doggies would be an wise decision. Pitbulls excluded.