As Apple's iPhones and other smartphones feature increasingly sophisticated cameras, processors and touch screens, the rise of the super-stocked device shows that even the inimitable Steve Jobs couldn’t predict the future.

The popular mythology around Jobs was that he was always thinking 10 years ahead of the rest of the computing and electronics world. Under Jobs’ leadership, Apple produced some of the most revolutionary and iconic pieces of consumer technology ever: the Apple IIc, the original Macintosh, the iMac G4, the iPod, the iPhone and iPad.

But the origin story of the first iPhone reveals that Jobs, while undeniably brilliant, was not a technological soothsayer who predicted our digital future. He was just trying to make a really cool phone.

Brian Merchant, author of The One Device: The Secret History of the iPhone, says that for all of the original iPhone’s game-changing innovations—the multitouch screen, the high-quality camera, the built-in accelerometers and gyroscopic sensors—Jobs conceived of the device as a cellphone, first and foremost.

And central to the concept of a cellphone back in 2005 and 2006 when the iPhone was being developed, was that it fit comfortably in your hand and in your pocket. “If the iPhone was uncomfortable to hold, that would have been a non-starter for Jobs,” says Merchant.

If you watch the 2007 Apple keynote when the iPhone debuted, the first thing Jobs says when he unveils the device is that “It fits beautifully in the palm of your hand.” Its size was perfectly suited for what Jobs believed was the original iPhone’s crowning achievement, making phone calls.

“We want to reinvent the phone,” said Jobs at the 2007 keynote. “What’s the killer app? The killer app is making calls. It’s amazing how hard it is to make calls on most phones.”

Merchant says that Jobs’ number one pet peeve, according to developers who worked on the original iPhone, was that his regular cellphone would drop calls. No doubt Jobs was jazzed about the iPhone’s groundbreaking touchscreen and Apple’s first-ever apps for music, photos, and SMS texting, but none of that could get in the way of making phone calls. The first iPhone shipped without the App Store, in fact, because Jobs didn’t trust third-party developers to prevent dropped calls.

“Which is insane to think now,” says Merchant. “Because the iPhone became famous for being kind of a crappy phone. The phone was the last thing anybody used it for.”

The iPhone took two-and-a-half years to develop and wasn’t even Jobs’ brainchild. In 2001, Apple released the iPod, a sleek, handheld digital music player that sold millions and catapulted Apple into the device market. Apple executives worried that the iPod would lose market share once cellphone manufacturers figured out how to put MP3 players on their phones. But not if Apple beat them to it.

The first prototype of an Apple phone shows just how stuck Jobs and his team were in existing technologies. According to Tony Fadell, one of the original designers of the iPod and the first three iPhones, the first concept was literally an “iPod phone.”

“It was an iPod with a phone module inside it,” Fadell told Venturebeat. “It looked like an iPod, but it had a phone, and you would select numbers through the same interface and so on. But if you wanted to dial a number it was like using a rotary dial. It sucked."

Jobs scrapped the design and started from scratch. At the time, there was a team of Apple engineers who had been playing with a device called the Fingerworks iGesture Pad invented by a man with hand injuries who couldn’t use a conventional mouse. Members of the team had worked on the Newton, Apple’s infamous flop of a PDA, but still believed touchscreens held promise.

“It was more of a ‘blue sky, future of computing’ kind of thing,” says Merchant. “The touchscreen research had gone through several iterations. It was briefly tied to a tablet, put aside, and had just kind of sat in the dark. Then Steve Jobs showed up and said, maybe this is the phone. Out of that mutation was how the iPhone was born inside Apple.”

With the touchscreen technology in place, Merchant says that many of the designers and engineers on the iPhone development team absolutely saw it as an opportunity to build an entirely new kind of mobile computer, exactly what the iPhone would become for its millions of loyal users.

“Steve Jobs didn’t,” says Merchant. “He thought it was cool, but the evidence suggests that Steve Jobs wanted to use Apple’s technology to build the best phone possible. And a phone fits in your hand.”

Subsequent generations of the iPhone stuck to the small design, incrementally increasing screen size, but nothing beyond 4 inches. Samsung was the first to release a truly huge phone in 2011. The Samsung Galaxy Note featured an almost comically huge (at the time) 5.3-inch screen and single-handedly popularized the term “phablet,” a cross between a phone and a tablet.

Jobs passed away from pancreatic cancer that same year. Whether or not it had anything to do with his absence, Apple released the iPhone 5 in 2012 with a noticeably larger 4-inch screen. Its first bona fide phablet was the iPhone 6 Plus, though, a 5.5-inch version released in 2014.

Simply put, the move toward larger screen sizes across the smartphone industry reflects the way that consumers are using their mobile devices. Jobs may not have imagined back in 2005 how the humble cellphone would become the primary platform for thousands of apps offering streaming music and video, real-time video chat, addictive video games and virtual and augmented reality experiences.

“The iPhone was designed to be a super slick phone in Steve Jobs’ mind,” says Merchant. “It was his development team and the demands of the user base that saw the potential in the new platform, that transformed the iPhone from a ‘slick phone’ into the culturally dominant, world-eating phenomenon that it is today.”