"what if they maintain that growth rate?"

That's a terrible argument structure. You might as well cut straight to "What if we just assume I'm right?" and be more honest about it.

http://www.joystiq.com/2010/04/23/xbox-division-posts-165-mi... says $165 million in profits on $1,670 million (1.67 billion) in revenue for the division. Saying "doubled their profits" sounds impressive, but it's not sustainable; say rather instead "increased their quarterly revenue by 5%" (or so, give or take a bit depending on the real numbers) for a better view of what that really represents. Still nothing to sneeze at (I'd take it), but not the same picture at all.