I'm really not sure if it's possible without sacrificing privacy or security. For instance, PGP isn't used en-masse either. We do see (alleged) e2e encryption in most messengers though; but it's definitely less secure and private than PGP, because often they can't be audited, don't have verifiable builds and there is no key exchange through a manual web of trust.
What do you think about OMEMO encryption used by XMPP protocol?
It is using open standard based on the Double Ratchet Algorithm, and it is said to have better encryption compared OpenPGP or OTR and it's much easier to setup.
I am not trusting any obscure encryption that is offered with telegram secret chat or with viber.
I was first confused, but XMPP = Jabber, I forgot about the name change! Honestly, I really like these types of protocols in general, that use federation, be it SMTP, Jabber or Mastodon; but I've not looked into OMEMO yet myself.
The sad truth is that they always have a hard time gaining traction since they don't have billions for advertisement and the majority of people doesn't want to set up servers themselves.
As I mentioned in the past though, I have a little spark of hope that with increasing power, efficiency and storage of common devices like smartphones and tablets, they could in the future allow application developers to bundle e.g. a Jabber server into the client application itself, as well as Bitcoin or full LN nodes (the latter already happens with Breez) within the apps, so users actually start to run nodes without setup and without even noticing.