As long as the KoF community around the world continues to support this game like they are now, then I don't think we need to worry about KoF dying out. So far, at every major KoF has garnered a really good presence, and in combination with the stream exposure it's getting around the world I think KoF is in good shape, at the moment. In North America, I'm not sure if entry numbers at majors will be able to rival SF4 or UMvC3 due to how difficult the game is for the casual gamer. I think Evo will be fine since it looks like top KoF players from around the world are aiming to attend. As long as we attend Evo (if possible) and hype the matches up then we'll be in good shape for the future. If the top KoF players from Brazil, Mexico, Peru, China, Korea, Europe, North America and Japan show up then I can't imagine how crazy the top 32 would look.
I think the rumor is that elive.pro's RF and Kindevu are going to play XIII since elive.pro LOVEs XIII couple that with Juicebox's own admission that he wants to play, Xian from SG and possibly even PoongKo...I think that there's a real good chance Evo'12 is going to be off the hook.
Really cool if RF and Kindevu are getting into the game. It also helps that eLive.pro is boycotting Capcom games, atm. lol