Thanks, Andy, for raising this question. Without a sense of what we are preparing for we can get caught up in a mindless accummulation of gear as we convince ourselves that "If I prepare for everything, then I'm ready for anything."
Some of us may have noticed this tendency on other preparedness/survival sites--this is NOT a problem on Equipped to Survive/Survival Forum--where every preparedness issue or question is answered by advice to add more and more gear, and where no BOB is considered adequate unless it has six knives (two of which have to be exotic specimens from the Himalayas or Indonesia), two axes, a field-grade FAK capable of handling multiple victims suffering a range of afflictions from arrow wounds to burst appendices, and two firearms with 1500 rounds of ammo. Again, I want to emphasize that this "more is better, and a lot more is a lot better" approach to preparedness is not a problem on this forum.
My approach is to go with the odds. I live in coastal California where the dangers of a major earthquake or a wildfire are much more immediate than the prospect of a general breakdown of society in North America. I have actually had to deal with both quakes and fires. So, I prepare for what is likely, not what is possible. As I've said elsewhere, in preparing I ask myself "What will I certainly need?" should the big quake occur, not "What might I possibly need?" It is much more likely that my family will have to temporarily evacuate to a reception center or "bug-in" at home for a few days until power and services are restored than have to take to the wilderness and fend off marauders in some post-apocalyptic world.
I prepare for what is likely. Am I prepared to deal with a comet striking earth or a post nuclear winter? No, but I'm really not that worried.