The shifting of the context here from the descendants of Nephi to the world in general further indicates that the vision is taking place conceptually outside of geography. While Nephi will see later that there are many waters between these Gentiles and his seed (see verse 10), to this point it is still not clear where his seed are located.
The vision is still dealing with future events, and now moves past the dwindling of Nephi's seed to the story of their reintroduction to the gospel.