I hope this is intentionally humorous.
For one, it is news when a life is saved by a gun-owner. The NRA and similar organizations make sure of it. Proven cases are extremely rare. 
"I've got a gun!" deters a criminal? Wonderful! Then no one need own a gun, just yell that out, right?
Imagine dozens of guys drinking late at night pulling out semi-automatic weapons in a dark, noisy nightclub, and blazing away at a perpetrator. 
Important note: "Dirty Harry" was fiction. Clint really didn't take on bad guys with semi-automatic weapons and blow them all away with his .44, remaining unscathed.
If more guns were effective, we'd be by far the safest nation on earth, long ago.
Now, I don't know how many gun owners deter crime, but both of us know how many die every year from gun owners' actions, don't we?