My "worldly" dad fought in two wars, was shipwrecked, and was stranded on an island for 3 months. Later he worked as a plant supervisor for a Silicon Valley Defense contractor making Nuclear Triggers, Microwave communications, reverse engineering of Soviet Tech, etc. He was a "prepper"...to a point. His concern was "EMPs" (Electromagnetic pulse tech) during the Cold War. He and his Military contacts felt it was likely the US "Grid" would be knocked out for a few + weeks. He insisted we be self-reliant for a minimum of 4 weeks. He even kept spare electronics in Faraday cages and insisted on a full freezer, generator, and garden. He said no one would survive a full nuclear attack, and that beyond 4 weeks the government would respond or we would all die anyway. :(
MOST USA disasters are relatively local (Wildfires, earthquakes, Tornados, floods, Hurricanes, riots), simply packing snacks, cash, important papers, photos, and laptops, and then driving 100+ miles away to hang out in a comfy hotel with a restaurant is our idea of a disaster plan. :)