Based on the post title and that the third map shares the same lines and has references to the Fallout series, I'm gonna guess part of the lore of the Fallout series is states becoming consolidated. At least that's the conclusion I came to after wondering the same thing myself.
It wasn’t until I was in a foreign language class in HS that our teacher called out this behavior. They said, if you ask for a “coke” in Europe, you’ll receive a “Coke.” We all thought that was odd.. At least at first.