Here's my take on it - I for one have "bought in" to several end-of-world chicken littles and none of them panned out. SHTF? Sure. Localized, as you have observed, is the typical issue. National? Too many movies have said this could happen. Look at Egypt *right now*... National unrest? Yes. National "chaos" like Mad Max chaos? No. Bosnian War, 1995. War! Everyone in their little gopher hole killing each other for food? No. Things that would concern me would be a polarized demographic such as gang wars in African nations. That would be a concern to me, as the entire "other side" would be more bent on systematic killings. Which by the way is why we went to Bosnia to begin with. Institutionalized killings of "the other side".
You simply can't paint the entire nation with one "it is going to happen" paint brush and apply the exact same conditions. You can't. Look at it from a "market analysis" point of view. You must analyze any "target market" to see how the demographics apply. In my neck of the woods, I'm happy to say they apply pretty well. Perhaps not a "you loot we shoot" mindset, but certainly above the line of animalistic behavior. Also the "help each other" mindset... the dude with the house generator has offered to let us power our deep freezer if something happens. He knows I have handyman tools and asks from time to time. The situation has already happened... hurricane Isabell directly hit this area in 2003 and no chaotic pandemonium from the ghetto hordes that set out searching for loot. Simply did not happen here, and mind you there is a large population of "poor" in this greater metropolitan area. Basically those people who rely completely on Wal-Mart and the grocery store for their sustenance. And would have no idea how to even start fishing, hunting, or gardening for their food. So... power and water out for 3 weeks. Worst case issue was long lines waiting for gas, etc. while everyone cleaned up the trees from the roads and their houses. If there were ghetto loot mobs, they stayed in the ghetto and no one heard from them.
Crime happens everywhere. That's just a fact of life. PROPER preparation is warranted. You simply aren't going to see blood-crazed droves of zombies coming to eat your brain. It isn't going to happen.
I guess my point is SHTF scenarios are simply incomparible to "end of world" situations. If and when another disaster strikes this area, I am certainly prepared in all areas. Gas, food, ammo, communications (everyone knows what to do) and preparation for "unexpected" things like water (I have my emergency barrel!) and things like chain saws, extra chain saw oil, rechargable batteries, a way to charge them without utility power, news services, yadda yadda yadda. Enough stuff to last a month before things get back to normal. In your area, you may be more prone to experiencing looting, blood-crazed mobs, etc. and then you must plan accordingly. "Bug out" to a safe area is IMO a good idea for that situation. I would probably jump in my sailboat and sail down the coast to a more hospitable area if I were located in that type of area. Here, I'm much better off just "bugging in".
If the world situation somehow degenerates into a nuclear or non-nuclear war and we are shooting at other countries, then that is the only "end of world" situation I cannot help. I can't live in a nuclear silo with my beef jerky for the next 20 years. What other kind of situation would be so detrimental to EVERY HUMAN BEING in the area that you would have to live in a hole? Terminator: Judgement Day? Zombies? Seriously? Unless the aforementioned polarization of "us" vs. "them" comes to fruition then I would not sweat it. And frankly what kind of situation would cause that? Religious zealots from the "other side" organizing and running around KKK-style looking to string up the competition? Umm... what else? Food riots where people are starving to death and looking for food? I simply can't imagine a situation where the ENTIRE NATION would be that bad. If and when that happens, you better be close to a good long-term food source such as near the coast where you can fish, or away from cities where the (deer) meat population is more populous. If we ever do have another Great Depression then you had better hone your gardening skills so you can convert your lawn to a huge garden. Yeah sure I've heard the phrase "we are only 3 weeks away from mass riots" talking about metropolitan reliance on The Supply Chain to receive sundries at their local grocer. But even during the "gas shortage" of the '70s I don't recall ever dealing with situations of no food.
My mindset is to just live life and be happy I have a "spare tire" plan for the odd times you may have a "blowout". If and when that happens, then I will don my best Grizzly Adams imitation and work and live off of the land. Again, PROPER preparation is warranted.
(EDIT - sorry for being so chatty, I think I had too much coffee this morning )