There were no fic fests organised in the archives or mailing lists (and to my knowledge, there still aren't)

This is my experience too. Why do you think this is? Is it because anyone can organize a fest on LJ, whereas in a forum or mailing list people feel like they have to be a mod or something?

Thanks for answering these questions. My experience at non-journaling fandom spaces has been so different, and I just don't understand why!