5. Continuity Is Not Top Priority
DC ComicsIf there's something we comic fans love, it's minutiae. Being able to pull out a reference to a storyline about a minor character from thirty years ago won't only win you a round of Fanboy Top Trumps (and no friends), it's also borderline required for you to actually read modern day comic books, which seem to draw constantly on old characters and situations, with the reader needing a certain knowledge to make sense of all the dramatic irony. Or just to tell who's who. In that case, it stands to reason that the people making these comics must be just as knowledgeable when it comes to continuity. Nah, they're not. Don't get us wrong, the reappearance of long-forgotten characters is often due to a writer or artist having a soft spot for them from their childhood, but nobody who makes comics is an expert on the character they're working on. Except maybe Dan Slott. Like we said before, the creation of a single issue takes so much time and effort that people simply don't have the time to be catching up on fifty years of history before working on a character. They just start working, and references and the like either occur naturally, are suggested by an editor whose job it is - sort of - to be the gatekeepers of continuity, or in the case of some writers they have an assistant who helps them out. When Kevin Smith wrote his reboot of Green Arrow he solicited the advice of a guy who ran a fansite for the character, and nowadays writers or artists can get advice from fans on Twitter, or even just peruse Wikipedia. They've used up all that space in their heads learning how to draw good and make words come alive on a page.
There's no room for Devil Dinosaur in there. More's the pity.