It's tempting to identify the iPhone (and smartphones broadly) and that's not totally wrong. Yes, it replaces a bunch of discrete devices from times past reasonably well for most purposes: telephone, still camera, video camera, iPod/Walkman, voice recorder, GPS, etc.

But that's not really what makes a modern smartphone so transformative. It's doing all those things while being essentially ubiquitous, mostly always connected, open to an amazing ecosystem of apps that take advantage of the hardware capabilities, and with access to an amazing amount of online information.

Modern smartphones are great products for the most part but it's how they function as part of an ecosystem that makes them transformative.