It was a nice idea, but the successor (and there will be a successor to OpenID) will be more flexible and the sole provider. It's the only way it can work.
Not really. The value for Facebook is in the data stored on Facebook's computers. Who provides credentials is not that important.
What's so special about a username + password combination vs. an openid?
Users, of facebook for example, will still provide facebook with their name, their phone number, their email address, their birthday, etc. Not to mention the torrent of information from photos, friends lists, likes, and posts. Consider that any site offering password recovery to an email address already effectively delegates user identity and verification to another site (the email provider).