You hit the nail on the head here. I'd add that if part of persona's success is tied to getting email providers to adopt it by becoming an IdP then it's likely

You hit the nail on the head here. I'd add that if part of persona's success is tied to getting email providers to adopt it by becoming an IdP then it's likely a flawed model. Why would google support/promote something that competes with Google+ sign up bit offers a poorer ux and robs th of the data they crave?