Episode 8 won't make the same business as 7, but that kinda goes without saying. Whether Ep.7 ends up at 2.2 billion, 2.5 or whatever, it is the result of a lot of people being curious and the hype being as massive as it has been. Even though most people really liked the film, the box is open now. A lot of people won't rush out and see the next, especially not 4-5 times. It's the same fate that awaits Avatar 2. But the thing is, these sequels doesn't need to top, or make as much as the "first". Even if Avatar 2 or Star Wars 8 only makes 1.5 billion, that's still crazy money compared to the budget.