What I'd like to see, and hardly anyone is talking about, is the cooperative model for this. Servers run by a community of interest; paid staff to manage the things which really require central clearing (anti-spam and anti-abuse in particular) and develop the system; users paying on an ongoing basis and being given a voice and a vote in the way the system is run. Federation with similar systems.
Bits of this exist already, but only on a very small scale and with the political/organisational infrastructure - basically individuals running Minecraft servers and the like.
I suppose I could gather thousands of recruits for something like this if I said "blockchain" a lot, but in truth it's the opposite: a system that requires users to trust individual other humans.