This is a really common suggestion, and I totally get why. It sounds like a straightforward solution. But unfortunately, turning a live-service game like Anthem into a fully offline or single-player experience is likely a lot more complicated than it seems.
Many of the game’s core functions, like login authentication, mission scripting, AI logic, world events, timers, and more, are all handled by EA’s servers. The client wasn’t designed to run these things on its own.
To make it work offline, you'd need to replicate or shift all that server-side logic to the player’s machine. That means increased CPU and memory usage, potential stability issues, and possibly much higher system requirements — especially since Anthem already pushes many systems hard as it is.
So while the idea sounds good on paper, the technical lift to make it happen could be enormous. Even more work than just finding a way to allow the community to host servers on their own.