Hah! Well, I've had experience with 'dying' communities before. Even Doom went through one of those phases: I have been following the posts on Doomworld for a few years now, and at one point, everything just stopped. No news for months, no updates in any sourceports, a severe drop in multiplayer games (as far as I could tell)...

Anyway, several months ago, just before the 15th (I believe) anniversary of the game, a couple of news items were posted, there was a sudden update for ZDoom after almost a year and the annual Cacowards were hosted. Almost instantly, it was practically the early 90s all over again. Even their Doom 3 community was put to shame by the old-school doomers.

Getting to the point, I think that this has the potential to happen with Jazz. Get something interesting to happen, such as a large tournament, and the community is likely to thrive once again. (Also, the release of the source code would obviously help, too - updates, source ports... Just look at what happened to Doom when the source was released. O.k., I'm starting to ramble, now...)