Please Riot do something about toxicity

This days, something like 1 ranked game out of 2 or 3 is just lost/win because one guy don't want to play the game and just ragequit or int after he gave out 1~2 kills (before you ask, no I'm not calling "int" when a player perform bad because of tilt, like many people do, just people who purposly lose games as they don't want their team to win for whatever reason). I feel like people are getting both bored of the game and selfish, so if they get behind they know they won't enjoy the game and don't care about the win, no matter how good their team mates are performing.

My last game for example, was just like that, our xin jungle didn't performed well at all early on, somehow all our lanes still won even if he did nothing for it, thanks to our mid Zed and me as Pantheon running around the map and making catch. So, then, without anyone flaming him, he just decided that our Zed and Twich were "kda players" and "don't deserve to win" (just quoting what he said in game chat), so he decided to do stuff like run down the ennemy base 1v5, stayed afk farm jungle when we took baron and when we tried to push with the baron buff ... This game was 99% won, but he decided this shouldn't be, so we lost.

You know what's the worst thing ? I don't think he will ever get punished for doing so. I've seen at least 20+ players acting like that in the past weeks, I reported all of them, and never got any feedback from the report system.

I think People this days know how basic the report system of this game is, and know how to play around. People don't afk anymore by just quitting the game so they don't reach the "2 minutes without any action taken limit" that would consider them afk, they just run around in base, using their spells randomly, while watching videos or reading a book. People write bad words like "tr4sh" or "ret4rded" or "moronn" with grammatical errors or numbers instead of letters, so the system don't detect them as bad words. I don't know if I should talk about this "technics" here, but I feel like everyone secretly know this rules and how to play around them, even if nobody is publicly talking about it.

Please do something about it, improve this years old system which is too basic, toxicity haven't been this high since season 2~3 when people were literally going 0/15 running under ennemy towers and asking each others to kill themselves.

(Sorry if this is badly structured or written, english isn't my native langage and I'm just sharing my thought as they come).