User blog comment:Jimeee/Bethesda Games Studios: "Moving to our next adventure"/@comment-1600847-20130416033919/@comment-5737364-20130416062755

@Draevan13

Fallout New Vegas was not called Fallout 4 due to it being a different company. (Bethesda made FO3, while Obsidian Entertainment made Fallout New Vegas.)

From what I hear, Bethesda plans to continue Fallout 4 in the east coast, while Obsidian recently voiced the possibility to make a sequal to New Vegas set on the west coast.

This, of course, sounds rather odd, but I'm excited nonetheless.