A: They don't maximize profits.
I was hoping that was an April Fool's joke but it is too consistent with the strip to be one. Today's strip proves me right (it wasn't a joke). Instead of buying the comic low and selling high (and what would make a more inelastic demand than trying to complete a comic book collection for your military son who is in Afghanistan?) and turning a nice profit, he gave Holly the Murdoch address so that she could cut out the middleman.