HAH! That's the first problem right there. League of Legends has the ABSOLUTE WORST community in the whole world. Everyone there is either a stupid flamer and can't show a little bit of good sportsmanship, or they're elitists that just bash on everyone because they're "pro". I've only seen one professional team in League of Legends that actually showed good sportsmanship towards all the other players, even when they lost horribly or were called out during broadcasts.
I also don't think that's really going to happen... There's so many games out there that are getting more and more popular, and really companies see that people want to just blow shit up, kill people in the most gory way possible, and feel good about it because they beat an actual person. That's why indie games are getting so big right now is because there's a big base of people that want to just relax a bit and have a fun and difficult single-player game to play. In the end though, I doubt any companies are going to make a co-op game with no PvP content whatsoever, it's nearly impossible for most games anyways.