Rage Quitting is a Huge Issue - Disappointed in Riot's Current System

Long story short, I'm in Plat 5 (big whoop) and I just played three 4v5 ranked games in a row. In each game, there was someone on my team who died 2 or 3 times in a row in lane and then said something to the effect of "fuck this" and went afk. Each of those 3 people have hundreds of games played on their account. How the hell don't these imbeciles who rage quit at a moment's notice in ranked games get permabanned by the time I play with them?

I wasn't born yesterday. I know this is very common in ranked games. But it did surprise me that this managed to happen in low plat 3 times in a row. Punishing rage quitting in ranked really needs to be a high priority as far as league punishment goes. At least I can play with a toxic player who continues to play the game and press buttons. Dealing with 4v5s you're just left waiting for the enemy team to push mid, sitting there under turret with the knowledge that your dbag of a teammate decided that because he lost his laning phase the rest of the game is over and done with, your 4 other teammates be damned. There just need to be harsher punishments for rage quits in ranked play. Period.

I've never seen any other game that has as consistent of a rage quitting problem as there is in League. I can only assume this is because the system is not good at punishing this sort of activity. Please Riot, fix this. Permaban these monkeys that ruin the game far too often!

Sincerely yours, This is Absurd