Ah, this reminds me of the good ole days.
I think everyone has a facet of the truth, and if you combine them, then I think we'll see the full picture.
My current home defense plan, for example, does not actually include a firearm. I don't have anything against incorporating firearms for self defense, but to me, a gun is only a tool. My strategy does not center around a particular tool. Rather the tools are centered around my strategy. And right now, I just don't have firearm within my current primary strategy. It's there as a back-up plan right now, though that may change in the future.
To me, the most important aspect of self-defense is the 3 Ps. Preparation, Planning, and Practice. If you do that, you are already 80% effective, with or without a gun.
Separately, I personally don't believe that deterrence is a good policy.... I see it only as a beneficial unintended consequence. If the bad guy runs from the sight or sound of your gun, all the better. But you don't want to bet your safety on it.... Some bad guys really are NOT in their right minds when they decide to victimize you. Plus, not all states legally recognize the use of guns as a deterrence. If you're not careful, it could land you in jail, especially if you discharge your weapon, even for a warning shot.
In terms of strategy, it would be best not to resort to lethal force until it is legally appropriate, and for that matter, as a last resort. However, when lethal force IS introduce, it is best to simply apply it as such.
That said, in practice, the adrenaline dump really does change things. When you're in that moment, everything except for your gross motor skills go straight out the window. And if you don't have any, you're going to simply stand there and freeze.
Um, sorry, but I'm getting distracted by lunch, so... maybe more later, maybe not.