Games are decided in champion select
They have a tank and you got Riven? Guess you lose.
They have a Janna and you got a Yasuo? Skip, go next.
Ornn vs insert bruiser name here? Too bad.
One bad pick, one bad player decides the entire course of the game. This is the meta we have right now. Tanks become unkillable, your friendly assassin rushes duskblade and 1-shots you, ADCs clean up the rest, easy.
Remember season 4? The one where it actually mattered HOW you played instead of WHAT you played.