I just opened up my cache of emergency food, most of it canned goods in 5 gallon buckets and all of it 5 - 6 years past its "best by" date. Needless to say it's being replaced, (time flies huh) but I have been eating it and its still good so canned goods are my cup o' noodles equivalent, I figure 3 - 4 cans of Chef Boyrdee whatever and a can of beans, veggies and fruit per day isn't too bad to subsist on. I was eating vegetarian for a long time so the stuff didn't get rotated properly, that has changed.
History is written by the literate.
The AR 15 is by default a defensive firearm, right out of the box. You don't need to get the adapter that makes it an "assault rifle" or the clips that allow you to fire "twice at once".
Why more than one gun? Each has different uses. Some are for hunting different game, or shooting different targets. Some are for home defense, some for personal defense. Some might be made illegal so yet more are required to try and fill the gap that would be left vacant.