I worked for a major RF test and measurement company when the first iPhone came out and everyone was blown away that a company could design and tool up production for a cell phone without tipping anyone off in the industry.
One seems to leverage the core competencies of an organization better than the other... One seems closer to starting from 0...
It was a ML company going from building ML for the internet to building ML for a car.
The first iPod Touch wasn't until September 2007, 3 months after the first iPhone.
When the iPhone 1 was released, the iPod range didn't have much on any other MP3 player. All the things that make an iPhone an iPhone - the touch-screen, multi-touch, iOS, didn't come from the iPod.
Perhaps iPod to iPhone wasn't quite 0 to 1, but it wouldn't have been much more than 0.001 to 1.
One seems to leverage the core competencies of an organization better than the other... One seems closer to starting from 0...