No, seriously. You all explain away lack of skill with lack of experience with the game...

... but neglect the fact that a lot of lack of skill comes from lack of intelligence. I can guarantee you BoxBox has a much higher IQ than the average Riven player. I can guarantee you that that Bjergsen has a much higher IQ than your average mid laner.

Once you get the basics of this game down (by Diamond IV, that should happen), you need intelligence to climb further and stay where you are.