Riot doesn't need to do anything. It's a free game. They are an unbelievably good company considering a few things:
A) How well balanced they keep their game. Say what you'd like about the state of jinx or the state of Kassadin, they are constantly balancing and rebalancing the champs in order to keep them in a good poisition.
B) How well kept the servers are, especially on the NA servers. Try playing in EUW (or from what I've heard anyway) and it's a lot worse. There have been a few brief outages lately, but really, 5 hours of no ranked and crappy connection games? Just do something else.
Point being, it's an unbelievably well kept free game. They don't have crap.