If you needed any more proof as to the relevance of the iPhone to Apple's bottom line it was there in last week's earnings call. The iPhone contributes just shy of 50% of Apple's profits. Is it any wonder that Apple has gone out of its way to so aggressively defend the iPhone's UI?
For Apple this means that September's iPhone 5 launch needs to deliver something spectacular, as the iPhone's market share continues to drop outside of the US and UK and Chinese sales have been less impressive than perhaps many would have expected. (That's not to say that they haven't been impressive though).
The images of the new iPhone seem to suggest a bigger device - presumably to house a bigger screen - but with a similar design to the current iPhone 4S. That's probably not going to do the job of bringing in users from devices like the Samsung Galaxy S3 and Note, even if it will probably be enough to persuade the Apple die-hards to update.
Siri was the big draw for the 4S - I wonder if Apple haven't got something similar hidden up their sleeves for September...