All the cool kids in the block eliminated the need to trust the provider decades ago. PGP: 33 years ago, OTR 20 years ago, Signal 14 years ago.
Signal evangelicalism needs to halt, you mean the Whisper protocol.
That said, what I would love to see ( and likely won't at this point ) is the world where pidgin could exist again, because everyone is using some form of sensible standards that could be used.. right now it is mostly proprietary secret mess of things.
And don't get me started on convincing anyone in group to moving from one ecosystem to another. Fuck, I just want email for chat that is not owned by one org.. Is it really so much to ask ( it is rhetorical, I know the hurdles are there and only some deal with human nature )?
You always forgot to enable OTR even if it was right there in front of you. You couldn't use it cross-device, and its 1536-bit DH got outdated without fixes. There's stuff like lurch that offer OMEMO but still, I really prefer that I don't have to think about key management anymore. With Signal things just work, and it's magical.
So, yes, trust is needed.
Having a single client gives you insane boost to security agility over decentralized alternatives.
Feel free to strive towards functional decentralized ecosystem that feels as good to use, then switching will be a no-brainer.
