Why?

Rito reworks a champion and creates a whole new champion with the sole purpose of forcing the meta to change; Morde "we duo-lane now" Kaiser, Lamb and Wolf-camp. Forgetting that only 2 out of 125 champions being able to do unconventional things doesn't change the meta.

Meanwhile the best players in the world, annually get together and showcase new inventive things or the pinnacle of skill. Some of things things were untouched for a long time, even the whole year (Such as TP's cooldown to towers buff), but the general population didn't see it. Afterwards most people try it out and start doing it, organic advancement of the game meta.

Riot: UUHHH OHHHHHHH TELEPORT WE'RE UNSURE IF WE REALLY WANT PEOPLE HAVING LEARNED HOW TO MAKE SMART TP PLAYS, I THINK THIS SPELL THAT HAS BEEN IN THE SAME STATE SINCE S5 STARTED IS TOO STRONG, uhhhhHHHHHHHHHH [presses Flash out of any discussion and goes to respond to some joke thread about a loaf of bread that looks like Teemo]