Apple’s problem, of course, is that it’s a one-product company—the iPhone still represents about 62 percent of its overall revenues—and sales of that product are down and are expected to continue falling. This leaves Apple vulnerable, especially since it hasn’t been able to augment or replace the iPhone with another hit hardware product, as it had in the past when it transitioned from Mac to iPod to iPhone.

Indeed, Apple’s other hardware lines—which include Mac, iPad, Apple Watch, Apple TV, and peripherals—are each challenging in that they sell in far lower volume than iPhone and are refreshed even less frequently. Apple’s traditional model of selling new hardware to new and existing customers each year has started to wear thin at the edges.