This game takes too much brain logic to teach someone how to play it
That's why it's uncoachable to any new players
Even AI mode is impossible to help a new player how to really play the game.
Because it doesn't teaches you about invade, macro, warding, it teaches you nothing beside turret range and damage from it. And also teaches you nothing but how fast can you end the game and how many kills can you get.
And then you have kids even in High Plat - Diamond who still has no idea how all that work either. When you have people who are that boosted and that bad who still doesn't understand about rotation and even some of the most basic and common sense of the game, how would a new player even learn.
That's why you see only Pro Team go for Challenger players and teach them about Macro only, because they don't have the luxury of time to teach some baddies how to play their Champs and the basic of the game