I'm still not seeing a distinction. Your email account is already a single point of failure for every account registered with that email that has a "forgot password" feature.
Maybe it would help if we considered two hypothetical scenarios. A: Your email is compromised, and you're registered on 15 websites with that email, each of which has a "forgot password" option. B: Your email is compromised, and you've used Persona to sign into 15 websites. In what concrete, practical way is B a more damaging situation than A?
Great point! And the recovery process is much easier in the Persona case... because you only have to fight to get back your Persona account. Today you'll have to
1) Fight to get your email account back
2) Visit each and every site and manually recover your account
Maybe it would help if we considered two hypothetical scenarios. A: Your email is compromised, and you're registered on 15 websites with that email, each of which has a "forgot password" option. B: Your email is compromised, and you've used Persona to sign into 15 websites. In what concrete, practical way is B a more damaging situation than A?