First paragraphs please. I am now blind. I read the first 9 words before I lost my vision.... Luckily I only needed the title.
See a concept a lot of people do not understand is every person Riot bans or punishes means a potential loss in revenue for them. Riot games is a publically traded for profit company. Even if Riot could instantly determine a violation with an AI system, they don't want to punish you to make you leave. They want to try to "reform you". Which means banning the few they have to and then trying to scare everyone else. But it means a lot of the toxic behavior is let go by Riot.
League by age demographic is probably between 14-24 for what I would guess would be 85ish% of their player base. Riot knows for sure. They collect age data. Most of the community are young immature people and they project whatever they are feeling onto others through League in an attempt to make themselves feel better.
They do this for 2 reasons. 1. Because Riot for the great majority let's them get away with it and 2. Because they are protected by anonymity through the security of the internet and knowing that the likelihood of ever playing with you again is slim to none. Point 1 exists in like every MMO, but point B is less common. See in a lot of other MMO games you play on a server, but more importantly you are tied to a permanent avatar AKA your character. If you are an A-hole that reputation sticks to your permanent character and people will likely not want to play with you. No one wants to raid in WoW with a jerk as an example. In league there are no clans, there are no in game avatars. You are tied to an in-game name which can be altered at anytime you like for 5-10 bucks I can not remember. Not that you ever have a reason to change your name since a huge majority of people never play with the same people again after a game.
A 3rd major cause of the toxic problem in League stems from how players are judged. My summary of ranked League is this.. It takes a team to win, but it only takes 1 player to lose. Meaning snowballing is such a huge problem that if one person does poorly and someone else on the team does not do really well to account for that.. than your team will likely eventually lose. A huge majority of ranked games work this way because people do not have the game knowledge to A. Not put themselves in these situations to begin with and B. They do not know how to recover from them.
So when at the end of the day if you lose. You lose LP. If you win, you win LP. Regardless of your participation in the match. So when you have players rank and points completely out of your control and in the hands of 4 other people it becomes extremely easy to get frustrated with another player. Because if they do poorly, you will lose LP even though you might be doing fairly well. It takes 5 to win, but it only takes 1 to lose.
Other games like CoD and Battlefield are different in the sense that win or lose, your score for the great majority is completely based on your individual performance. If you have a 30 KDA and your team loses, you still gain a crap ton of experience. Not how league works. League is the opposite. You could have 30 kills and somehow you make 1 mistake, die and your team loses.... Not only do you not gain anything, but you are punished lol. It is extremely backwards.
Now to your point. Do I agree with you that this game would be so much better and satisfying if Riot took really any measurable steps towards the problem? Absolutely. Are there plenty of steps they could take that would ultimately lead to the potential of additional revenue while still drastically improving their game experience? yes. Than why does Riot still refuse to do anything after 6 years? Answer is because they do not need too. While I personally have taken the smallest stand I can and refuse to give Riot anymore money, plenty of people still are, and plenty of people are still playing.
Like all other major companies such as Riot the only way to get them to initiate change would be by hitting them in their pockets. All Riot has to do is keep the servers online, keep the store open, and provide a stable(ish) online experience and the game will continue to be successful.
