From the same post-mortem video:
former BioWare executive producer Mark Darrah revealed that internally at the studio, the shooter had code for local play and private server use until a few months before launch. Presumably, it's still there to be "salvaged and recovered."
"Anthem actually had the code for local servers running in a dev environment right up until a few months up to launch," Darrah commented. "I don't know that they still work but the code is there to be salvaged and recovered."
https://www.windowscentral.com/gaming/anthem-is-dead-after-t...
There is maybe some hope archivists will find a production build of Anthem in the wilds of Steam versions with that local server code still accessible in some sort of debug flag and then reverse engineer some of the other live services Anthem depended on.