Welp. One thing is most people built fallout shelters (build bugout bunkers) for their families; so, maybe that's not directly "personal safety". At any rate, there is also a general belief among preppers that they are a set of people, a group inspired to be prepared; this generally also defines those who do not prep as not prepared. So, you are talking about society but the preppers see two societies. The preppers have websites, books, tv shows, and more. Just as an Army prepares in units, those who built a fall-out shelter were not preparing in isolation. They did not expect they would be the only persons to survive. One can surely argue the inability of hostile forces to build and deploy a nuke is significant: seems some relationship exists between the intellect needed to make these things and the intellect needed to refuse to make or deploy these.