If you drop by an army/navy surplus store looking for, y'know, surplus stuff from the military, you'll be out of luck. In less than 20 years, they have changed from being the go-to place for getting an olive drab field jacket to Apocalypse Outfitters. They may even have some kind of zombie / prepper window display just to clue you in to the theme of the merchandise.
This shift in the nature of the surplus store is important because it shows how broadly the survivalist phenomenon is affecting our society. It's not just wackos on internet comment boxes, or colorfully paranoid subjects cherry-picked for reality TV shows. There's enough demand for this stuff in your own neck of the woods that they have managed to convert the surplus store into a preppers' emporium.
It also underscores one of the key differences about our age's doomsday survival movement, compared to the nuclear fallout shelter builders of the duck-and-cover era half a century ago. Today's preppers are going about their plans in such an individual-focused way that there aren't any well known suppliers, either public or private, whose central visibility would serve to warn the not-so-prepared and perhaps convince them to make themselves better prepared. You have to already be prepping-inclined to be in the know about surplus stores actually serving as intro survivalist stores.
Today's preppers are only trying to cover their own ass, and at most their nuclear family. (My impression is these folks are less likely to have children than normal folks are, but it's not as though they're mostly lone wolf Rambo wannabes.)
The preppers of the '50s through the mid-'60s had an entirely opposite plan -- to save the whole community, and hopefully the whole society, through establishing a social network of prep centers, which individuals and families could plug into.
Although they valued having a fallout shelter for their own private dwelling for the benefit of their nuclear family, they also made sure that there were communal protection spaces that could house hundreds or even thousands of citizens. These were mostly housed in public buildings -- churches, schools, libraries, and the like -- although a handful of private buildings, like local banks, signed on too. Such communal spaces carried distinctive signs on the outside to inform those who didn't already know.
Municipal governments allocated funds to supply the shelters with food, water, first aid kits, and so on. They also coordinated a wide communication network that would get the word out in case of emergency. Ordinary citizens volunteered to staff these local emergency communication networks.
In general, the Midcentury spirit was one of civic engagement to preserve the entire community, in contrast to the contemporary spirit of civic withdrawal to preserve Number One.
The main factor seems to be the status-striving and laissez-faire norms of our age, and the accommodating and regulatory norms of the Midcentury. If the goal of life is to climb as high as possible on whatever status mountain you've chosen, then everybody else's survival is their own concern. You may not specifically wish them ill, but hey, let them save themselves if they're not as awesomely advanced in survival tactics as you are.
The preppers give off such a strong air of trying to win a status contest amongst themselves, that it's hard not to link the trend to the status-striving trend. I can survive three weeks, not just two. Yeah, well I can recycle my compost into two different kinds of gluten-free muffins. Psh, you guys can't tie as many kinds of knots as I can. Yeah huh, and we've fired more guns than you have. You wish -- have you guys even raised chickens, or are you all just vegetable gardeners? And so on and so forth.
Browsing through old pictures and stories about the Midcentury fallout shelters reveals no trace of an atmosphere of one-upsmanship among their builders and owners.
You could also explain the timing by pointing to the strength vs. weakness of civic institutions, which parallels the accommodating vs. status-striving phases of the cycle. Maybe folks back then were more communal in their doomsday prepping because they had all kinds of thriving civic institutions to plug into and hit the ground running, while today's preppers look around and see an ever-decaying public system and figure why bother serving on the crew of a sinking ship?
That would confuse cause and effect. Civic institutions come from people, not the other way around (except on a long-term evolutionary time scale). Civic life was thriving back in the Midcentury because the people followed a norm of reining-it-in and making room for others, and civic life is so dilapidated today because people are too busy striving to boost their own status that things which benefit others will just have to wait until later (i.e. never, since status is a constant treadmill pursuit).
We also see the self-focused and striving nature of the prepper movement by looking at how it varies over geography. Looking through Wikipedia's summary of episodes for Doomsday Preppers, a reality show, you find very few subjects from the Deep South or Appalachia. They are far more likely to hail from the historically rootless areas farther west, beginning around Kansas and Texas, continuing on into the Mountain states, and extending all the way out to Alaska and Hawaii. It's striking how many preppers are from the West Coast.
Those places also tend to direct their status contests toward lifestyle pursuits rather than sheer wealth accumulation, which makes them more susceptible to a lifestyle contest like prepping.
Communities are more tightly knit in the Deep South and Appalachia, so they don't worry quite so much about a major disturbance. Not that it wouldn't send shockwaves through their communities, but the support networks are already woven tightly enough that they don't have to worry about being carried away by the flood. Some isolated transplant in California or Colorado, however, could see his entire line go extinct from the softest shift under the ground. He is a much more natural convert to the survivalist self-help movement.
You know who doesn't need to join the survival movement? The Amish. Not because they're already used to a lower-tech, off-the-grid way of life. But because they're all part of an interconnected and humble community, whose complexity can support a fairly decent standard of living by global standards. You can't get that complex of a group when everyone is looking out for themselves, or at most their nuclear family.
Who were the best prepared nation during the nuclear fallout shelter craze? The Swiss, whose Sonnenberg Tunnel (built in the '70s) could have protected over 10,000 citizens not only from the radioactive fallout but the initial bomb blast as well. Public shelters like that were an extra backup layer in addition to the household shelters that were required of new homes at the time.
The Amish are just a splinter group from the Swiss and broader Alpine German population, so this is no coincidence. If we want to survive like the Swiss, we ought to interact like the Swiss, not by turning every activity into a self-promoting status contest.