Rumors of a bigger iPhone, though not as persistent as rumors of a less-expensive iPhone, have persisted for a couple of years now. While rumors of less-expensive iPhone, in the form of an iPhone 5c, have increased, parts have leaked out, and it seems like a real possibility for release this year - perhaps as soon as the iPhone event on September 10 - not so for the bigger iPhone. For the bigger iPhone, there have been no name leaks, no part leaks, no nothing. So where is it?

The big fallacy about big phones

Big phones are nowhere nearly as popular as people - especially tech geeks - think they are, at least not in North America.

Back in January of 2013, 9 out of 10 customers on AT&T chose the 3.5 or 4-inch iPhone over all other smartphones, including all bigger smartphones, combined. 6 out of 10 customers on Verizon did likewise. In the last quarter, reported in July of 2013, more than 5 out of 10 customers on both AT&T and Verizon still chose the 3.5 or 4-inch iPhone over all other smartphones, despite the iPhone 5 being halfway through its product cycle, and the presence of newer, bigger rivals like the enormous Samsung Galaxy S4 and the gorgeous HTC One, as well as various other, larger Android, BlackBerry, and Windows Phones.

Again, those aren't just iPhone vs. big phone numbers. Those are iPhone vs. all other smartphone numbers, small, medium, and large. And given those numbers, there's nothing but predictions and smitten tech journalists and geeks - including yours truly - wishing it so to support the argument that Apple needs to make a bigger iPhone.

It's also not the only answer.

Bigger phones as faster horses

A bigger iPhone is only one solution to a specific set of problems, and Apple is famous for thinking differently.

When people said they wanted a netbook, Apple understood they wanted lighter and smaller, and gave them the MacBook Air, and cheaper, and gave them the iPad. When people said they wanted multitasking on iOS, Apple understood they wanted to play Pandora while surfing the web or answer Skype calls while checking their email, and gave them specific API for just that. When people say they want bigger iPhones so its easier to read and they can see more content, Apple might, for example, give them iOS 7 Text Kit and deference and call it a day.

People tend to describe the solutions they think they need rather than the problems they're experiencing, yet many companies respond to the former rather than doing the much harder job of figuring out the latter. Not Apple. Apple figures the hell out of that type of stuff.

Yet a bigger iPhone does best address one specific problem.

Bigger phones for more of the market

Despite the lack of market demand and the potential to solve some of the problems in other ways, there's still a couple of reasons Apple might be considering a bigger iPhone.

First, bigger can be better for some specific use cases. It also increases addressable market. That's why we have two sizes of iPad now.

Right now, if a customer does want a bigger than 4-inch phone for their use case, they have to choose between the iPhone and something else. Even if vast amounts of customers, like AT&T in January 2013, or just over half like AT&T and Verizon in July of 2013 do indeed choose iPhone, some portion of the other half - and we still don't know how big that portion is - chose to give up on Apple and go with a larger display.

That's not dissimilar to 2008-2010 when the iPhone was only available on AT&T, and that meant no iPhone for people for whom staying with another carrier was more important than running iOS. In order to continue to grow, however, Apple wanted to reach those customers. So, in 2011 they came to terms with Verizon, then Sprint in 2012, then T-Mobile in 2013, and now there's almost no carrier barrier for the iPhone in the U.S.

As smartphone penetration increases, and higher end smartphone sales head towards saturation, increasing addressable market in other ways becomes just as important to growth. The iPhone 5c could do that for people for whom price is more important than running iOS. A theoretical bigger iPhone could do that for people for whom size is more important that running iOS.

There's currently three ways other companies compete with Apple in phones: price, size, and not being Apple. The last one will always be there, the first one looks like it's about to be addressed, and that leaves just one more on the table.

The road to 5-inches (redux)

Back in January I did some math and figured out that if Apple used the iPhone 5 display at iPad 4 density, it would result in a nearly 5-inch iPhone. That's exactly the reverse of what Apple did when they used the iPad 2 display at iPhone 3GS density, and shrank it down from 9.7- to 7.9-inches for the iPad mini.

That approach seems to fit Apple's pattern of making life as easy as possible for manufacturers and developers by sticking to the same screen densities and display targets. However, even if held slightly further from the eye by virtue of its slightly larger size, such a 5-inch iPhone wouldn't be as sharp as the current 4-inch iPhone 5, much less 1080p, 400+ppi Android phones, and iOS 6 and previous-style interface elements would be a little big.

Apple could mitigate against that by going to 4.7-inches, or even 4.3 inches (what Android manufacturers absurdly call "mini" these days") but it would mean not using the iPad 4 display density, adding slight complexity to manufacturing, and it may not be "big enough" to expand the addressable market enough to warrant the additional product line.

Apple could also mitigate by going to @3x resolution - 1704x960 at 391ppi - but that also adds complexity to manufacturing, would compel developers to create a @3x assets for their apps, and for all the gain in pixel count, still doesn't hit 1080p. Going to 1080p throws all of Apple's old conventions out the window, and going to @4x resolution - 2272x1280 at 522ppi - even at 5-inches is, frankly, insane.

All this by way of pointing out it's far easier to say "Apple should make a big iPhone" than it is for Apple to do what they'd insist on doing - making a great big iPhone.

iOS 7 and a bigger iPhone

One of the biggest differences between previous speculation about a bigger iPhone and now is iOS 7. When a company like Apple goes to all the trouble of building a physics and particle engine to support their interface, when they objectify it and gamify it and make it a dynamic, living thing, it opens up a lot of potential. When you add Text Kit to mix, and the design language in general, and when you see what it all looks and feels like on an iPad mini, then the possibilities for a bigger iPhone next year become infinitely more exciting.

So where is it already?

To date, Apple hasn't expanded the iPhone line. Ever. Apple has stuck to one new phone a year, every year, since 2007. (And most years they hit constraints even doing that.) This year, we're almost certainly getting an iPhone 5s-class update to the existing like. If we also get the less expensive iPhone 5c, it'll be the first time we to two new phones a year. It's not impossible to imagine them eventually going to three new phones, but it's difficult, and certainly not all at once. Two phones, like two tablets, two MacBook Airs and Pros, and two iMacs, would seem to serve the biggest swathe of the addressable market with the smallest range of products.

The less expensive iPhone was under consideration for many years, and Apple seems to have waited to get it exactly where they wanted it to be, in terms of cost and quality, before moving it into production. I wouldn't at all be surprised if the bigger iPhone was going through a similar process now, with Apple making sure that if and when they do start to kick it out the door, it's an Apple product, from display to positioning, that gets the kick.

Maybe that'll be next year.