thats if valve wants to sink so much $$ into LoL
the real reason LoL is so successful is riot sinks a lot of $$ into the esports scene, making it popular.
The amount of $$ Riot puts as tourney winnings is ridiculous
then again, when you're backed by a multi billion dollar chinese company, you can do it =D
Which is also a big part of what Valve has been doing. The last International was the biggest tourney in terms of payout and production value outside of Starcraft.