I wonder if it may not be that humans are irrational actors so much that they have insufficient data and may not strictly speaking be optimizing for avoiding shortages.

I could see people being upset if they knew that eggs where out because some rich person bought a disproportionate number of them; it's just that normally they can't know.

I think that most people's preference for limited resources would be a low price with a limit on how many a person can purchase (which is what many stores do during shortages). It seems to me that people care more about making sure that everyone can get some eggs without being gouged than they care about avoiding shortages in aggregate.