I know right - they are all recommending Signal, Wire, WhatsApp, etc., but these aren't alternatives. They are all centralized, controlled by a single entity even if the underlying protocols are open. And you're right, they are instant messaging - ie. alternatives to Messenger, Hangouts, etc.

We need a modern email replacement that is decentralized, federated, et al. Something that keeps all the modern cryptographers happy, while facilitating the same kind of long form conversations and federated self-hostability that email provides.

I think Matrix is getting there, but even that is still focused on instant messaging.