Rebecca Solnit wrote a book, "A Paradise Built in Hell", on how people behave during disasters, and found broadly the same thing - contra the prepper myths, most people most of the time faced with disaster come together to work cooperatively to help each other.

We're a fundamentally social species - we've got smaller brains than Neanderthals did, we're not a particularly tough species, but we're very, very good at cooperating with each other.