Bill Lund was among the founders of the massive entity we now know as the Comic-Con International. He writes…
Regarding your mention of the con being too big and not concentrating solely on comics, well, I had this very discussion with several con attendees last week. From its inception, the con had always focused on comics, science fiction and films. In fact, if anyone has the earlier program books — which, sadly, I no longer have, myself — when the con was known as Golden State Comic Con or West Coast Comic Con, there were three circles in the logo that featured each subject as mentioned. Our featured guests in those earlier years, besides such luminaries from the comics world like Jack Kirby, Mike Royer, Russell Myers, Russ Manning, and Neal Adams, included Ray Bradbury, A.E. van Vogt, Forry Ackerman, Kirk Alyn, George Pal, Bob Clampett, June Foray, Edmund Hamilton, Leigh Brackett, and Frank Capra. We even had Chuck Norris demonstrating martial arts. Therefore, San Diego's convention, under whatever name it used at the time, featured various artists from each field of interest.
It was George Lucas and Charles Lipincott who had the foresight to showcase Star Wars at the con that showed the rest of Hollywood — eventually — how important the Comic Con could be to their films and tv shows.
I have all those program books and Bill's right. I don't know what the mission statement says (nor do I know anyone who ever reads mission statements) but a key concept of the San Diego Con was always that comics intersected with other media…and were perhaps in some ways legitimized by those intersections.
The other point I should make is that it isn't just that the convention caters to Hollywood and other non-comic concerns. So does almost every major news site that purports to cover the world of comics. Most were more interested in that stuff than in the programming and presences that were comic-specific. That's kind of the way the whole comic fan community has skewed the last few years. Whether we like it or not.