The game is retarded
It doesnt matter if you are good. It matters if you have decent team mates.
Oh you have 5-0 and 1 item tier ahead. Dont worry, you get insta killed by a 0/2 veigar with skilless ultimate that does 50% of your HP.
You are ahead and you pushed other lanes. Doesn't matter bot will dictate the game.
It's a fucking game of who has the worst teammate. Really.