One thing I did want to point out about media cons vs lit cons is that I honestly don't think lit cons absorbing the media natcon has killed media fandom in any significant way - media fandom just went off and reformed in new ways.

Here in Perth Swancon continues to tout itself as the only significant show in town, while the local anime convention quietly has an annual attendance ten time larger (@3,000 people). I used to run a Star Trek club with a monthly attendance double that of an average Swancon.