[kory]

The UX isn't the most looming problem, but it's one that needs to be solved. My question is: How in the world would you convince people to use keys to verify their accounts to one unique, anonymous, identity, as the OP suggests? I just don't see it being something people would spend the time to do. Not to mention, getting to a "Login with Google" level of UX, available as universally as "Login with Google", would be extremely hard without a centralized authority.

The bigger problem is convincing people that it's worth switching. Apple is the closest to doing this with "sign in with Apple". "Sign in with Apple" hides your identity from the client site, the value prop is clear for the user, and the process as close to frictionless as possible. But the solution is still "centralized". Apple stores all of the information to make the system as frictionless as it is.