Twitch+f2p, specifically DOTA. Something will eventually topple DOTA games, and whatever does that will be even bigger. Having watched the essential crash of SC2, I think the biggest lesson learned should be accessibility. While the complex, strategic nature of SC2 makes it perfect for professional play, it provides quite a barrier for casual players. Blizzard essentially asked people to buy a $60 game they'd probably get stumped in over and over. And unlike Brood War which had the casual friendly, super popular maps like Big Game Hunters there really wasn't anything similar in SC2.
Meanwhile LoL and DOTA2 are easy as fuck to play, and both Riot and Valve did a great job building esports awareness among their player bases by having in-game streams; meanwhile there were tons of new SC2 players who had no idea about the pro scene. Blizzard's take on esports basically revolves around pumping money into it, whereas Riot and Valve are more community based IMO (based on what I've seen/read).
I think esports is here to stay. The corporate side will rise and fall, as it has always done, but the player base for these f2p, accessible games will just keep growing until the next big f2p thing arrives.