I could imagine some kind of federated Reddit where HN could be a community fully managed by dang et al. according to their own needs/wants.

Then you just subscribe to each community as you like. Much like you can unsubscribe to all the default subreddits and only subscribe to the subreddits that interest you, only this time you don't have Reddit 's commercial interests/standards hanging over your head with the power to shut you down.

Granted I'm not sure of the value (other than censorship resistance) vs. a set of fragmented, specialized forums we had way back when.