There's many solutions ive heard like
- Associating an account with a Gov ID so bans are more permanent
- Maybe a reputation system? get kicked enough, or downvoted enough and you get permabanned
- many channels like ltt on the wan show and SomeOrdinayGamers (and many others) have talked about it extensively, but there's always a drawback
All these options are based on some level of trust with someone or something and can be easily taken advantage of, but these are concepts nonetheless.