Ban people from ranked? Can we do that?

Uh, if u go 4/21/3 or something like 3/18/3 etc... in many many games... why are u still allowed in ranked? If u get this guy on ur team, u have such a large decrease in chances of winning those games. Idk, I just think there should be a message telling that person "Sry, u need more practice before ranked" or "Play 15 more normal games before going back to ranked".

OR, just give them a 45 LP loss per lost game... cuz these people somehow stay in their rank, yet they literally always do badly... They either have luck of facing an equally bad person so its basically a 4v4 or they have luck with an amazing team that carries them constantly... But how can you do so badly in 80-90% of ur games and yet lose like 19-20 LP.... and gain the same... That limit should be waaay bigger.

if its 48 kills in a game, and you got 6 participation, no towers, no drakes, no herald, no inhibs, basically no wards placed. Then even if its a win, please... please decrease their LP... idk fuck.