The disruption in the iPhone was technical, social, political and economic.
[0] http://reviews.cnet.com/smartphones/at-t-8525/4505-6452_7-32...
The functionality was really already there. The "disruption" was aesthetics, marketing and ease-of-use.
And in the end, it's a phone, not a cultural revolution.
While I think this is mostly true (Nokia fans love to point out that every possible smartphone feature appeared on at least one Nokia product which may have shipped in the 1800s), there is one way in which this simply is not true, and it's a way which really did change everything.
The browser.
The difference in 2007 between browsing on the iPhone and browsing on any other phone was kind of like, well, comparing desktop Safari in 2007 to trying to browse in 2007 with Netscape 4. Maybe not quite that good. Phones often had only one font available to them, had very limited CSS support, often had no Javascript support. Windows Phone and the Nokia Communicator were the best of what had been out before then, and to say "they were for nerds" is an understatement. Only nerds would tolerate them.
Look at articles after the iPhone's introduction about data usage -- it absolutely skyrocketed, and it was all being driven by the browser. For the first time people actually had a real web browser in their pocket, and it really did make all the difference.
It wasn't just a phone by any stretch -- what made it disruptive was that browser in combination with the touch UI (by far the best way to use a browser on a pocket-sized screen). Revolutionary, or evolutionary? You can make a case either way, but the iPhone didn't upend the smartphone market just because it was pretty and had great advertisements.
And the fact that the old windows phones crashed daily. Was riddled with bugs (some never got fixed) and from an accessibility point of view was a terrible piece of hardware. Good riddance.
Apple made the smart phone easy to use, and gave it much needed elegance. Over night it turned the smart phone market into a consumer smart phone market.
Now it seems like "most people" have a smartphone of one type or another. That's a huge change.
The iPhone (and smartphones in general) have disrupted multiple markets: * Photography and video * Portable music players * Email and messaging devices * Phones ... and many others
The thought I ran into many times with many people during this "disruption" period basically went along the lines of:
"I could buy a new camera, a video camera, a new iPod, a netbook, GPS device, etc - or I could just get an iPhone."
The old windows mobile was a complete dog. Let's take just one example, individual processes could only be allocated up to 32 megabytes of RAM. Really. That's one reason why it could never have run a decent browser, or really a decent anything else. That alone rendered it fundamentally crippled compared to iOS full 32 bit preemptive multitasking kernel. Yes iOS is fully multitasking, only user apps are restricted in their multitasking privileges by the sand boxing system, but background services have none if those limitations.
It was limitations like this that meant projects like Courier would never have been able to compete with iOS. It's why Microsoft had no choice but to develop an entirely new OS core for their mobile platform, losing crucial years of competitiveness.
Google was lucky. Although Android was never originally intended to use multitouch gestures or an accelerated UI layer, at least it was based on a Linux core so had the fundamental technical underpinnings to support competitive application level services. This gave Android a few years head start on Microsoft, even though they were a few years behind Apple, just enough for them to occupy the low end of the market and eventually mount a credible challenge in the mid and high end.