the double-spend problem is unrelated to account-association (KYC, etc.) problems, solving the former doesn't solve the latter
the core problem with keypair-based systems is that people will lose their private keys, and that has to be accommodated, which requires trust delegation, which blah blah blah we've already worked thru these issues 1000 years ago and the result is representative government
the core problem with keypair-based systems is that people will lose their private keys, and that has to be accommodated, which requires trust delegation, which blah blah blah we've already worked thru these issues 1000 years ago and the result is representative government