MedWheeler said:
Bad guys shot by cops are far more likely not to cease to be a threat than bad guys shot by would-be victims. This is because bad guys shot (or shot at) by would-be victims do not expect said shooters to pursue and try to apprehend them if they turn tail and flee. Cops will, and the bad guys know that.
And you know this... how?
The assumption is that you HIT the target -- easier said than done with a moving target (which doesn't wait for you, like a paper target.) Most often, when you read of attacks, it comes quickly, with little warning, and often from behind or the side. It may take longer to get your weapon out than you think... Home invasions are a little different, and they CAN (not WILL) give you a bit more time to get ready.
Some bad guys have been shot before, know what it feels like, and will keep on coming. Others will duck and run with the first shot fired. No two bad guys are really alike.
The scenario presented above doesn't address whether the bad guy is rational, on drugs, is desperate, etc.
The real world doesn't look the way you describe it... Even a .45 might not be enough with SOME bad guys.
And then, there's the other scenario -- which is arguably more likely to happen in many places where readers here live: a small group of dogs decide to make you lunch. We've had a number of dog attacks in this town over the past year (and we do have leash laws, etc.), with several people badly hurt.