It's hard to imagine a day when the iPhone is no longer the cash-generating powerhouse that it currently is. But everything has its time - just ask the desktop PC or the iPod - and as we move our gaze from the short and medium term out to the long term, it's possible to envision a time when the iPhone is no more.
But there does that leave Apple? Right now, Apple's success is tied to the iPhone, with this one product pulling in a good two-thirds of its revenue and profits, with a big chunk of the remainder tied up in one way or another to it.
So if Apple wants to remain the tech powerhouse, it has to be thinking and planning about what comes after the iPhone.
But, how exactly do you follow the iPhone?
This is something that Piper Jaffray analyst Gene Munster has been thinking about. In a note to investors - and seen by Fortune - Apple's future lies in virtual reality (VR) and augmented reality (AR).
"As a starting point, we expect in the next two years Apple will add VR to the MFi Program (Made for iPhone)," wrote Munster, "which should make it easier for third parties to build virtual reality headsets powered by the iPhone, much like Samsung's Gear VR today. In the next 5-10 years, we expect Apple to release a mixed reality headset with the long term goal (15+ years) of replacing the iPhone."
Now Munster doesn't have a fantastic track record when it comes to Apple predictions. He was the analyst that long-believed that Apple would unveil a TV.
"We believe 10 years from now Generation Z will find reality inefficient," Munster went on to write. "Generation Z will see the benefits of mixed reality headsets that augment the world with real-time information as they need it and in their field of view, without needing to look at one piece of information at a time on a smartphone."
This might all seem rather far-fetched, but how would we have reacted to a prediction made, say, in 2000, that smartphones would be as huge - not to mention hugely influential - as they are now? We'd have probably thought that was far-fetched, but here we are, a little more than 15 years on, pretty much every one of us with a smartphone.
It's also not that wild a prediction, given that Google, Microsoft, Facebook, and even smaller players such as HTC and Samsung, are getting involved in VR and AR. It would be sort of weird is Apple wasn't investigating this avenue.
But whether anything comes of it all is a different matter.
Some argue that Apple has its finger firmly on the pulse of technology, and has managed to capture lightning in a bottle at least twice - with the iPod and then with the iPhone. Others look to Apple's more recent endeavors - specifically the iPad and the Apple Watch - and think that Apple's lost its spark and is grasping at straws.
And let us not forget that Apple is a company that's flush with resources, sitting on cash reserves of over $200 billion. With that sort of money you can't rule anything out.
But the real question isn't what Apple's working on, but what will the tech landscape of 2026 to 2031 look like, and how that landscape will be divided up amongst the players.
Another important point to ponder on - and one that I'm surprised that Munster didn't address - is whether the iPhone has 10 to 15 years in it. In ten years the iPhone will be 17 years old, and that would be a really long arc for a single product, especially one that's already showing signs of weakening.
And finally, the real zinger. How long until Apple needs a replacement for the iPhone? I mean, look how quickly the bottom appears to have fallen out of the iPad.
What do you expect Apple to be doing in 10 to 15 years? Do you think people will be walking around with VR/AR goggles attached to their faces?