Lots of games stale when the times change.
Guilty Gear is a great game, but when new things come around, it was bound to diminish, unless there's a gigantic center around it, like in Japan.
Once/if a new GG comes around, no doubt a revival will follow instantly (no exaggeration).
But until then....it's really just a lack of scene interest.
If there was a scene around DBZ Budoukai Tenkaichi/Raging Blast, hell yeah I'd be involved, but due to lack of interest, it's a sad truth.