This milestone is remarkable, especially as Apple is accelerating its sales pace. Since the iPhone’s launch in 2007, it reached a billion sales by 2016, nine years later. The next billion took only five years, and the third billion just four years more. Given the strong preference for iPhones among youth, particularly in the US, this growth trend appears set to continue.

However, this reliance on a single product is risky. Apple’s Eddy Cue recently acknowledged that an iPhone may not be necessary a decade from now. This presents a concern since phones are Apple’s main business. The company’s significant exploration into future technologies hasn’t garnered major success, and its initial AI efforts didn’t greatly impress either. From an external perspective, Apple appears unprepared for the potential future landscape a decade away.

This issue is evidently recognized by Cook. In the earnings call, when questioned about the future of phones as the dominant mobile platform, he stated that Apple is considering other possibilities, believing that emerging technologies will likely complement rather than replace phones. While phones seem secure for now, the innovation by figures like Sam Altman and Jony Ive could potentially impact Apple’s journey to its fourth billion iPhone sale.