People were saying SC was dying five years ago, but it's still very much alive. Even if WCG stopped hosting SC, Korea still has Starleague, SKY, OSL, etc. It's difficult to get an 8 player ffa game or a 2v2v2v2, but a simple 2v2 or 1v1 is still very easy, there's plenty of people still playing. The great thing about StarCraft is that you can go to UMS when you're bored with melee, then switch back when you grow bored of UMS. The game remains fun after years of play.
SC may die in 3 years, 5 years, 10 years, we don't know; but I'll be playing for a long time. StarCraft is one of the best games I've ever played.