Every apocalypse story does this and while people would hoard as seen by current events, everyone didn't go "every man for himself" or "give me all your goods" overnight. This whole thing in end of the world stories where people would turn on each other soon as things remotely go bad always seemed unrealistic to me. Sure, give it a little time and people will form factions and those factions might go against each other, but it's not like we have a whole lot of lengthy human history in which modern society with technology and trucks and planes, etc. delivering food in your supermarket wasn't a thing. People lived without that and people would live without that.
So of course, the author had to force MC to be right.