Earlier quoted context omitted.
> Yeah, but this actually works. Exchanging public keys worked for decades before blorkchains were even a word.
This depends what you mean "works", if it's meant on the technical conceptual level that yes, of course, I think no one would disagree. If it's taken to mean had widespread and growing usage at the social level, then I think that's hard to argue.
How do we know who is behind a hash? Because there is a server (aka. a "centralized authority") that has that information.
So how exactly is that different from using my google account to login to some webservice?