Back in the day, Riot had a challenge for people (Known as the 'Level 20 Challenge'). In it, Riot picked players who had messaged support and whom support believed genuinely meant to reform after the perma.
So they said: If you can level a new account to level 20, without it being punished once, you can have your old account back.
95% of people, people who Riot thought were genuine and repentant,_ failed_ the challenge. If that was the people Riot thought were genuine, what about the people who are still salty or frustrated about their ban? Do you think that even 5% of them will manage to reform?