Although plenty of recent silver screen young adult adaptations (Harry Potter, Hunger Games, etc.) ended on fairly definitive notes, the Twilight series actually still has plenty of narrative threads still in play.
If Meyer wants to go down that road, then the folks at Lionsgate will be there to support such a decision.
Patrick Wachsberger recently spoke to ScreenDaily and admitted that the ball is really in author Stephenie Meyer’s court with regards to another entry in the Twilight saga.
If Stephenie Meyer wanted to pick up the story of Edward and Bella several years after the events of Breaking Dawn — Part 2, it wouldn’t be terribly difficult for her to do so.