Such networks already exist. There's a reason most people won't use them: moderation.
Most people don't want to spend their time on 4chan. If you want interesting content, then you want users, which means you want moderation.
The problem with moderation is that it's a hierarchy. That's exactly what a decentralized network exists to avoid. We need a decentralization-compatible moderation alternative. I think reframing top-down moderation as bottom-up curation could work.
Freenet's FMS+WoT seemed like a good moderation solution: subscribe to your moderator of choice.
4chan's problem isn't a lack of reputation system to game, its problem is a number of state actors and ideological groups pouring resources into bot campaigns meant to derail discussion and demoralize users. Psywar is afoot!
Most people don't want to spend their time on 4chan. If you want interesting content, then you want users, which means you want moderation.
The problem with moderation is that it's a hierarchy. That's exactly what a decentralized network exists to avoid. We need a decentralization-compatible moderation alternative. I think reframing top-down moderation as bottom-up curation could work.