If I spend ten hours drawing something, I don't see much of a problem selling a $2.50 print of it for $7. I kinda feel like my time and energy is worth that much, at least.

Also, not that you care, but the vast majority of Artist Alley types are lucky to break even at a con, even if it's a local one. An AA table mostly just allows us to be able to afford going to the con in the first place.

And really, nothing's stopping fic writers from printing up books, particularly when the property in question wasn't originally text. Except worry that no one would buy them, I suppose.