Yes, the secret sauce here is potentially Automattic. With WordPress.com, Gravatar and a substantial hold on WordPress.org, they have a rare opportunity to create a centralized platform.
I feel like there is a massive misunderstanding of what Jetpack does and provides in the way of a social network. All indications I've seen is that Jetpack just shares to other social networks. It does... effectively nothing... to provide an alternative free of other social networks.
I mean, you even call out Gravatar as being "owned" by Automattic. I don't mind Gravatar but it's a bit stale and certainly not in the vain of a distributed or "open" social network.
Maybe I'm misunderstanding but I don't see how Wordpress is anything like a social network other than you citing the fact that it can tie into other ident providers and share to other social networks. That describes... a metric ton of sites out there.
It may not even be the vision they have for Automattic ... but I do think it's an opportunity they have.
For Gravatar, no it's not a social network at all, but it's a potential part of a bigger, wider identity platform.
If we're just discussing Automattic becoming a closed Facebook competitor, sure it's possible. I think they have the position to do so, but I'm certainly not interested in another closed platform, even if bits of the core software are free.
Gravatar is a wider identity platform, but it too just piggy backs on email. It's an avatar platform that piggy-backs on the email identity platform. And sadly, the avatar platform isn't distributed either.
In my opinion, BrowserID has a much better chance of being the technical and featureful identity provider. Anyone can be a BrowserID provider and provide any level of security from literally none to quadruple factor auth with PKI if they wanted. I would love to see proposals on how to layer functionality like Gravatar on top.
That's a social network alternative that I could get excited about!