Your trying to apply logic based upon your life experience where neighbors help neighbors as I would too. But the entitlement mentality of the people may think and behave otherwise...
Yes, there will be some who act as barbarians, who revert to a feral existence. But how long with those live? How many of those will move away from the cities and toward the farms? Those that move toward the farms, how many will find an Amish community?
Most of those with entitlement mentality will die off quickly because they don’t know how to survive without someone helping them. That’s the point of the entitlement mentality.