These protocols exist, e.g. on top of I2P network.
Thing is, nobody has any incentive to back them.
Thing is, nobody has any incentive to back them.
Maybe aiming a lower tier of security (like what TLS offers) is good enough for regular user. For example, Matrix or Jami.
But the problem with Matrix and Jami is that these are still too complex for regular user. No user, no motivation for the developer and it's a downward spiral from there.