I think you're taking it too far to the extreme. We woudn't be isolated and alienated to the point where countless hordes of people would swoop down and attack our every belonging simulataneously with the sole intent of destruction and murder. Could it happen? Yes. Would I react the same as a New Orleans style SHTF? No. It's all cirumstance.
If we lost power on a state level and stores were being looted and nothing else, I would lock up in my home, arm myself and my family, and wait patiently doing what I could with what I had. I wouldn't sit outside and shoot at everything that moved towards my house. I would foritify and defend.
Now if police and martial law failed, that would be different. You can be damn sure that I would be taking a more active approach to defending my family.
Now this is all talk out my ass, because 90% of us have never been in that situation or even had a loaded firearm aimed at us with their intent being to kill. A good majority of us have probably never even been in a real fight where blood was shed. So when I hear people say things like "I'd get my guns and go SOCOM on their asses" (which lets face it, a lot of people say in these types of topics) it makes me laugh and worried, because I don't know if they will panic and really do that or if they will freeze up in fear and just be a target with a loaded weapon.
I learned long ago, pick your fights. I got in an argument with my brother, he pushed me and I hit him in the face (first time I ever actually hit someone) and he fell into a nearby weightbench. I was so shocked at what I had unintentionally done that I didn't even try to block him when he came back at me. All I know was I remember not so much the pain from the hit, but the sharp cracking pain as my head hit concrete floor. I blacked out for several minutes, I am told. That is the only REAL fight I have ever been in, and I learned you don't act rashly, because people who start real fights are there to fight.
I remember one time in highschool, when my now fiance was with her boyfriend who was also a friend of mine, and he got angry because she liked me. He got infuriated and started hitting me. I just blocked what I could, and laughed the rest off (which of course pissed him off more). I don't need to prove anything to anyone, and it would be stupid for me to fight back over something stupid like jealously. It would be the same as shooting someone who is tagging your house or something stupid. Some things you should just let go. Now had he touched my fiance, I would have knocked his teeth in. I know it, because there have been several times where someone has tried to do something to her and I step up to them and let them know they won't do it easily.
I guess my point in all this is my fiance is above all, the most important thing in my life. Period. I would die for her without hesitation (as it should be). If a SHTF scenario happened, in all honesty, I would rather let someone take my truck than fight about it and possibly end up having my fiance pay the price. I won't hand it over, but I won't shoot out for it. If someone is willing to kill my fiance and I over a truck, then let them have it. I would rather have her than some damn truck. I do know that I would sit awake all night just to make sure nothing happened in her sleep, I know, I HAVE been there. If trouble comes my way, let it come, nothing will stop it. I just hope it isn't after my fiance, or it will have more than hell to pay.
Being prepared doesn't mean having the supplies to survive, it means being mentally aware of what you are capable of doing and what you are willing to do to survive. Having MREs, water, and firearms are all great, but it doesn't mean a damn thing if you aren't mentally prepared to handle the situation. Please, get all the supplies you will need, just be sure you know what you will need to do, becuase sitting around a camp fire enjoying stale spaghetti and crawling off to your sleeping bag for a nice night under the stars while the crickets chirp is not how it will be. The worst of humanity will hit, and I sincerly hope that if (when) that day comes, you are all prepared and get out ok, and not just you, but your loved ones too.
ETA: Sorry, I kind of went off on a huge tangent there.