It isn't? Just out of curiosity, does anyone have some real metrics here? An 8 megapixel compressed image from what I can tell is ~4 megabytes each (someone please correct me if I'm wrong). So that's well over 200 photos just for 1 gb. Are people really storing *thousands* of photos on their phones? And someone mentioned that 10gb = 1 hour roughly. Even Apple touts "The videos you shoot on iPhone 5 are 20 percent smaller in file size but retain their full-resolution quality." so it may be less. I can't imagine the average user is taking more than 1-5 minute video clips made for youtube consumption.
On my iPhone 4 I've never gone above 2gb in photos/video use myself, so I'm not terribly worried, but am curious what a similar usage would scale to. Certainly not double? I only tend to keep stuff on my device I haven't synced up elsewhere - so at most, what I would store on say a two week vacation.