You're absolutely correct. But unless the tools are designed so the average user can easily manage their own keys, it's basically PGP again.
I think U2F/WebAuthn dongles actually could solve this problem but there are all sorts of new problems now like "how do I use this with my iPhone and also with my PC" or "what happens when lose my (physical) keychain with my dongle".
The Signal protocol is very well designed but the implementation requires a telephone number (I know it is coming). That's a step removed from PGP which can be completely offline.
