It is indeed very complex to do while staying decentralized. But it's also one of those areas where it would be fine to not be fully decentralized IMHO.
For the patreon etc use case we could have everyone post their pieces as encrypted using a public key and then a central server (or multiple that communicate) could then decrypt on a per-front end basis where they decrypt the text only to users who pay.
There are also other challenges with encryption key leaks etc which makes it quite hard. Secrecy and public ledgers were never really a good mix.
I think it's a problem that should be solved outside of hivemind. But I don't mind making a proof of concept to show some examples to users :)