The increased inflation rate in the 1960s, the US monetary devaluation, the continued concern over a possible nuclear exchange between the US and the Soviet Union, and perceived increasing vulnerability of urban centers to supply shortages and other systems failures caused a number of primarily conservative and libertarian thinkers to promote individual preparations. Harry Browne began offering seminars on how to survive a monetary collapse in 1967, with Don Stephens (an architect) providing input on how to build and equip a remote survival retreat. He gave a copy of his original Retreater's Bibliography to each seminar participant.
Based on this crude but honest assessment of the general public's affinity for the common bicarbonate, you'd be surprised by how much survivalists are into it (#2 on the list of "things for preppers to hoard"). They must expect some pretty serious hankerings for tasty leavened baked goods, or they have extensive phobias about the funkiness of their nuke survival backup plans.
However, if some tales of survivalist stockpiling are to be believed, our nutty neighbors have enough of the social lubricant squirreled away to hold the most epic end-of-the-world-party of all time outside of Edgar Wright's social circle. It might not be practical, but who needs practical when you and everyone you know is doomed to die from radiation poisoning or cancer?
Earthquakes, tornadoes, and hurricanes can cause you to leave your home or even be trapped there. Roads could be blocked due to fallen trees, power lines, or even damaged earth from the natural disaster. Rescue crews can not be in all places at once. You may have to wait it out for quite a while before its over. You won't be able to go to the store or to the corner market.