Apple had a plan when they introduced the iPhone. The iPhone was going to be your new pocket computer—easily at hand all the time. No bigger than a handful (and at the time, even a 3.5” screen was considered huge for a phone). It probably would’ve gotten thinner and thinner, until it became like the iPod touch 5th generation. (Have you held one of those recently? Pretty amazing.) iPhone app developers were given tools to carefully craft apps at a fixed screen size.

It’s been said that the iPad was in development even before the iPhone, but the phone was going to be the generate more money because everyone had a phone. So the tablet form factor (the iPad) was going to be an accessory. After being wowed by an iPhone, users would eventually want something that wasn’t so pocketable, but still booted up instantly, was thin & light & touchable, very secure, and ran the same apps as their phone.

That was the plan.

But a funny thing happened along the way: 

The Phablet.

Yes, the phablet. Android phone manufacturers, Samsung in particular, were driven to out-innovate the iPhone in the only way they knew how: specs. And what spec is more visible than size?

So Android phones, which were initially even smaller than the iPhone, grew year by year. They grew way beyond even what Samsung probably thought they’d grow. Soon, big phones weren’t big enough: we needed phablets: half phone, half tablet. The Samsung Note series was the best seller of these.

This threw a wrench into Apple’s best-laid plans.

Meanwhile, Apple started working on the Apple Watch. I don’t know what really happened between Jony, Tim, et al, but I imagine at some point someone had an “aha!” moment* when they realized they had to give in to this elephantization of phones into tablets: What if we give in and make large/huge phones, but we make the watch become the new always-at-hand computing device (and, jewelry. And if it’s jewelry, think of the profits! But I digress…)

One hopes that watches won’t grow any bigger than the Apple Watch, that humans have a limit to how big a device they’re willing to fashionably strap to their wrists. So the watch becomes a more-or-less fixed target size for developers and UX people and UI designers.

But the phone—oh, the phone! Now it is free to grow and grow and grow! When will it stop? Who knows? Will it grow bigger than the iPhone 6+? Probably. As big as an iPad mini? Can’t really say.

But what clearly is happening is that the phone is becoming the new tablet: a fairly big screen that’s great for photos, maps, web pages (although who uses the web much, anymore?), video/movies, Office apps, and generally viewing and editing content of any kind.

And the Apple Watch is the new, always-at-hand device that you interact with all day long (perhaps to the chagrin of your coworkers and/or lunch date).

*—or maybe this was the plan all along. Maybe they’re even smarter than I think?