I get the sense from your comment and link that there's a real risk that Persona will be abandoned in a few years?
Persona ain't going away so long as we're still relying on it.
For a more informed answer, you can ask the team directly in the mailing list or IRC channels listed at the bottom of https://developer.mozilla.org/en-US/Persona#Join_the_Identit...
[Edit: Or see callahad's reply in this thread.]
But it's open source :) we're still working on getting it there. The next release will dramatically scale back the API complexity, lock in the APIs and data formats, and pave the way for native browser extensions, self-hosted polyfills, etc.