“I guess small communities must band together. But that community had better not include a hungry man with a rifle.”
Yep...and unfortunately there are a lot more people with rifles than serious preppers, so most typical communities, other than possibly Mormons, will have a lot of leachers running down the supplies of the preppers.
The novel “One Second After” is about an EMP strike on the USA and the aftermath for ordinary folks. It doesn’t take long for marauding gangs to form and take what they want from the weaker citizens. Then the marauding gangs turn on each other in increasingly violent warfare. Total civilizational collapse is not a pretty sight.