Until there is an incentive to rehabilitate your account, no one will stop trolling.
I have a major problem with the honor system and that problem is that there is no incentive to fix your account and therefore behavior.
I have been perma banned 6 times now. I keep a rotating stock of accounts. I try to be good but sometimes I tilt and get aggressive. Which leads to the problem.
Once you tilt, and are punished that's it. The account is now locked at 0 honor, its a "criminal"~~ so any report counts more toward it~~(shown below to not be true, thanks), future punishments are harsher, it takes months to unlock; and thats just to get back to honor 0. There have been people who have been punished, put on their best behavior and then slipped up for ONE game and boom, weeks of ban.
With all of the above, there is no incentive to fix your account. Why go through all that trouble of months, with punishments, unable to earn rewards. When you can just make a new account level to 30 easily?
There is no incentive to fix your behavior so many people don't (myself included). The SECOND my account is punished, that just becomes my new troll account. I make a new "main account" and when I need to let off steam and intent feed/scream/etc I just use the old one.
And the thing is, riot is VERY bad at catching troll accounts. So I can troll hundreds of games on an account i no longer care about because whatever.
And now its even better because I dont have to buy skins or anything. I just re-earn them, and the the RNG; maybe Ill get ones I want this time.
Edit
Another good point was mentioned below. The system also ruins the new player experience because it encourages people to roll fresh accounts. Some of the worst games I have ever seen are with new players, being crushed by people just there to make new accounts who are some of the most toxic people ever as they are only there after being banned.
Edit 2
I think that after discussing the issue is partially that there isn't as much clarity to the system as there needs to be. There isn't enough warning when you stray from the path, and there isnt enough feedback when you are trying to reform.