The idea behind the 72 hours (and it’s something many countries encourage) is so that the emergency services can focus on vulnerable people for the initial phase of the emergency. Able-bodied, fit, uninjured younger people can sort themselves out while people in emergency services can manage the emergency.
After that, there should be some order of some kind in most emergencies.
I just did emergency/disaster management training so I’ll be hauled in to help, and fed and watered if something happens.