Great topic!
I see the trend too. It's interesting to see other people's takes on it. I think they're just giving us what we want to see...although it would be interesting to know why that's what everyone wants to see all of a sudden. Sort of like why is everything zombie-this and zombie-that now days? Does the collective subconscious know something we don't?
Or maybe they just realized "hey, everyone sure liked Burt Gummer...let's make a bunch of shows about those types of weirdos!"
It was kind of hokey, but I liked seeing how the people from Discovery's
The Colony put their skills together and "survived". And I always thought that the first season of Jericho was eerily like a post-nuke how-to series.
I've always been interested in that type of thing but it wasn't always so mainstream. I've always liked fishing and hunting and have always grown some of our own food and generally liked DIY type stuff. I like being self sufficient, whether it's TEOTWAWKI or not. We've got some minor preps, we try to have enough stuff on hand for immediate problems (bridges/roads out, occupy riots, etc - realistic type stuff that could keep you from getting to the grocery store as often as one might be accustomed to) as well as a little bit of longer-term stuff in case there is a zombie apocalypse.
The idea of having a variety of calibers for a "doomsday" scenario is a good one if you're bugging in or if you have a deuce-and-a-half to bug out with but, like you say, can get impractical pretty fast. I see a good, practical BOB (bug out bag) as containing some extra socks and other "useful" clothes, a few days worth of food, a knife and/or multi-tool, something to make fire with, some paracord or sturdier rope, local/regional maps (along with a compass and orienteering know-how), a handgun in a common caliber and some ammo for it. If there's room a small, light rifle or carbine or a shotgun wouldn't be a bad idea. Come to think of it, it's a lot like what I'd take on a remote camping trip and there's probably a reason for that.
Something like that would be a decent kit that could go far in a variety of situations and could easily be tailored to individual needs. It's got the basics (stuff to keep your warm, fed, protected, etc) and could get you by for a few days in anything from riots, zombies, Red Dawn invasions, mad cow and/or bad lettuce outbreaks, long-term power outages, comic-book villain attacks, etc. If nothing else, it buys you some time to let things settle down, get your head on straight and figure out what to do next without having to venture out too far for those essentials.