Re/Code was recently able to obtain a few slides from an April 2013 Apple presentation that Samsung presented into evidence last week. The slides show that Apple's sales team was well aware that smartphone growth had begun trending towards cheaper sub-$300 devices and larger screened devices.
The chart title above is pretty damning, reading "Consumers want what we don't have." So even though iPhone 5s sales thus far have been extremely robust, the underlying take away here is that Apple could potentially reclaim some of its previous iPhone growth levels should it decide to release a larger screened iPhone model later this year.
iPhone 5s demand notwithstanding, it's undeniable is that iPhone growth has been on the decline in recent years. The chart below speaks volumes.
As for the reasons behind diminishing iPhone growth, the Apple presentation highlights the following explanations.
All that being said, the evidence that Apple has plans to release a larger screened iPhone later this year continues to mount. To that end, it's worth pointing out that Tim Cook explicitly stated during a February 2014 interview with the Wall Street Journal that he's not fundamentally opposed to the notion of a bigger iPhone. The hold-up, Cook explained, was that Apple is unwilling to make any of the user experience trade-offs that often accompany larger screened devices, such as reduced battery life.