Hubzilla also doesn't federate with NNTP and MAPI, or even telegraphs [shrug]. If you want to interface with legacy technology, we let you do so with plugins; but that's not what hubzilla is. Hubzilla is a web publishing platform with decentralised access control and some unique cross-domain and DNS-independent identity provider services. OStatus? It sends (public) messages back and forth. That's pretty much all it does and pretty much all that it can do.

We aren't in the same space as GNU-Social and Mastodon. We aren't even in the same freaking universe.