Why isn't Moonshadows entire family and United States?

It seems there might be a misunderstanding in your question. If you are referring to a specific family or context related to "Moonshadow," please provide more details. However, if you mean why a fictional character or narrative doesn't encompass the entire family within the United States, it could be due to storytelling choices that focus on specific themes or characters, leaving larger groups or settings unexplored for narrative depth or focus.