Why is there no Champ mastery cap for ranked?

Ranked is not for learning, ranked is not for experimenting, ranked is not for filling a role. Ranked is for people to play their best champion in the best environment, with the best team performance. There should be no Top laner using Jax because someone said he was OP. There should be no wanabe ADC main that doesnt even have at least level 4 mastery. There should be no Cho mid that never used cho before in his life! Its annoying that me and many other people get paired with dumb players that dont even know how to play the champs they choose, let alone grasping the basic concepts of the game. I cant even push out of bronze because for three games in a row I have been paired with these types of people. COME ON RIOT. LISTEN TO THE ANGUISHED CRIES FROM HELL!!