My problem with the self-hosted model is that I don't trust myself to get it right and/or keep it updated. My problem with the 3rd-party model is that I don't trust them, either. So, lacking trust in either myself or the third-party, I'm just one of those people you can get only via secure e-mail, clear-text SMS, or whatever well-supported encrypted service happens to be the one with a plurality of users in my friend/family group. Clear-text sucks, but it can be used to negotiate a secure channel.
Unfortunately, the levels of spam in my traditional telephony services have dramatically increased in recent years, and as a tradeoff, I've just gotten harder and harder to get in touch with directly as I increasingly default to ignoring more and more methods of communication. I don't even think I'm someone with anything to hide or anything to fear my communications being in the public, there's just too much information to manage.
Blockchain-based solutions like Status.im appear to do away with these sorts of issues through decentralization -- but you still have to put trust into their network.
Solutions like TLS & OMEMO over Tor for XMPP seem to be a very strong privacy-centered solution outside of blockchain-based applications.
All Matrix homeservers and bridges are open source. I self host some of them myself. Have been doing that long before Element One was a thing.