The right intrepation is that Mozilla is not funding the project, but the protocl (browser id) and Persona source code are still out there.

The downside is Mozilla MIGHT sunset their Persona infrastructure one day. But that's not a real concern because Mozilla is never interested in being people's Persona verifier. They were hoping Persona would take off and people would host their own bridge, instead of relying on Mozillia's.

Persona was not discontinued. Persona lost active development and marketing. A wrong decision, but not one that affects the protocol itself.