The point isn't the "what-ifs" we can't do anything about. What if a meteorite fell on my head when I stepped out the door tomorrow? Not a single flipping thing I can do to prepare for that one. However there are things we can prepare for.
Also Walmart no longer sells guns. Haven't for years...might want to do your research better next time.
And what if the hypothetical wife had enough situational awareness to avoid the hypothetical rapist in the first place? One other "problem" with gun statistics is that the very people who carry guns are, by and large, the people who are least likely to ever have to use them. They must be more aware of their surroundings (a), to avoid having to use their gun and (b), to prevent their gun falling into someone else's hands. Sure, there are a few morons out there who carry guns and haven't really got a clue what they're doing; however they are the exception and not the rule.
The reality is, for some reason, the human race has a propensity for being an unpleasant, murderous species. Perhaps it's our creativeness; the 9-11 terrorists definitely had access to guns, but they wanted to make a much bigger statement. So they flew jets into the WTC, Pentagon, and almost the White House, and thousands of people died. No, I'm not saying guns could have stopped 9-11 (though actually passengers on the jets carrying guns could have stopped the terrorists, or at least brought the planes down without hitting anything...the passengers would have died, but the death toll would have been far lower. And Flight 93 clearly showed the passengers were willing to do so). What I am saying is that, if a psycho wants to kill someone or hurt someone, even if he can't get his hands on a gun, he'll find a way to do his thing if he really wants to. A gun happens to be the best defensive tool in existence, since carrying a broadsword around tends to attract goggle-eyed stares. Again, those of us who carry guns don't do so because we're afraid. We arm ourselves because there are things we value highly enough to defend with our very lives, if necessary. And because we choose to make that commitment, we choose the best tool available to use for the job at hand. Which the gun just happens to be.