I don't think most people, be it high or low elo take Ranked seriously enough or stay competitive.
So many times I see people just playing to farm up their lategame fantasy build or fucking around when they could simply end. Or people who straight up don't care about winning and just play the first 15-20 minutes then they get bored or something and start doing really stupid stuff.
But the worst scum are people who put their ego over gaining sweet LP and chat 60% of their ingame time. That is the main reason people are or become toxic - observing other people obviously being less passionate and competitive.
So maybe make Ranked Solo a much harsher environment, so that only people who truly want to be competitive play there? Maybe ranked anxiety was a good thing. Maybe having to play ALL ROLES was also a good thing.
I reached Gold 4 this season, but I know I don't truly belong and it was just statistical luck, because you are either playing with or against people who are not truly competitive and just wanna play a game and see where it goes -.- . I should be in Silver.