The iOS SDK is not quite as malleable as Android, and adding a resolution that is not a scaling of the current one would be rather problematic. Also, a 4" iPhone would be wider, and less comfortable, than a 4" Android, if proportions are kept.
This means that Apple cannot simply decide to make a bigger iPhone because it would either be less comfortable than the current one (and lose compatibility with some Dock accessories) or require a big modification in the iOS SDK, so I think that they will simply go ahead with the 3.5" as long as they can and plan their upgrade to a bigger resolution taking all the time they need, and only when the market really looks fed up with the current 3.5".
That's a pity, because I would kind of like switching to iOS, but I couldn't ever put up with an iPhone screen size. I have a 4.3" Galaxy S2, and I'm thinking about switching to a Galaxy Note.
This means that Apple cannot simply decide to make a bigger iPhone because it would either be less comfortable than the current one (and lose compatibility with some Dock accessories) or require a big modification in the iOS SDK, so I think that they will simply go ahead with the 3.5" as long as they can and plan their upgrade to a bigger resolution taking all the time they need, and only when the market really looks fed up with the current 3.5".
That's a pity, because I would kind of like switching to iOS, but I couldn't ever put up with an iPhone screen size. I have a 4.3" Galaxy S2, and I'm thinking about switching to a Galaxy Note.