I don't really get your point. Every app is "social" these days. Even health care is, at the core, a social network (you, your doc, your pharmacy, etc). So, what I am proposing is not against what you highlighted.
Every event kind in Nostr can be seen as a separate censorship-resistant social network. So, in many ways, Nostr has already forked itself multiple times. In fact, I do believe every client is also a fork of the network because no client displays **everything** the Network has yet. No client is complete. On top of that, every client does things differently. So, in some sense, they are all forks of the network.
There is no consensus layer in Nostr. We don't select a single chain like we do when we run Bitcoin. So, the idea of forking the protocol itself doesn't really many any sense.
To conclude: Forks are either already happening with all event kinds or it's impossible to fork because Nostr already includes everything. There is no in-between.