Ranked LP for intentionally feeding / Rage Quit's

Why is there no system in place that compensates the other players on a team where someone is intentionally feeding or rage quits or goes afk during a game? Most of the time I feel those that violate these rules during a ranked game aren't even punished yet the other people on the team who had to deal with them receive an lp loss and a "better luck next time". How come is there isn't a reduced LP loss for the other players who had to suffer for 20+ minutes when the game is so team reliant and you are down a member? Something should be done to punish those who cost their team a win such as a harsh lp loss or demotion, and the other 4 should receive a light lp loss compared to a normal lp loss for something out of their control.