For the most part, when people talk about "The Fediverse" they mean ActivityPub based sites. You could argue the point, since NNTP is "federated" as well, and one could certainly conceive of federating between the NNTP space and the ActivityPub space.
I'm a Fediverse user, fan, and advocate (mindcrime@fosstodon.org), but I specifically mentioned Usenet, because the "thing I want" in this context is, in fact, Usenet. Now if somebody wants to do the work to rebuild the Usenet hierarchy on top of the "wild west" that is the litany of servers on the Fediverse, build client support into Thunderbird, etc., then sure... that could probably turn into something interesting.
You wouldn't have liked Usenet in its heyday
Please don't presume to tell me what I would or wouldn't like. That's incredibly disrespectful. And in point of fact, I did like Usenet in its heyday.