Cook told Fast Company that the company hasn't put any sales expectations on the watch because the need for an iPhone 5, 5c, 5s, 6, or 6 Plus to work "creates a ceiling."
But the watch will be an important step forward for the industry, just as the iPod, iPhone, and iPad were, because it will create a new computing experience.
"The inputs that work for a phone, a tablet, or a Mac don't work as well on a smaller screen," Cook said. "Most of the companies who have done smartwatches haven't thought that through, so they're still using pinch-to-zoom and other gestures that we created for the iPhone."
That's why Apple developed new ways of interacting with a watch, like force touch and the Digital Crown. Force touch, or a harder press on the watch screen, will bring up an expanded set of options in various apps.
"People didn't realize they had to have an iPod, and they really didn't realize they had to have the iPhone. And the iPad was totally panned," Cook said.
Only later did people realize the usefulness of the iPod, iPhone, and iPad. Apple Watch could be in the same boat.
The misperceptions about Jobs
Cook's close relationship with his predecessor Steve Jobs has been well-documented, but Cook told Fast Company that people have this notion of Jobs as an overbearing micromanager. That wasn't exactly the case.
"He made a lot of decisions. His capacity was unbelievable. But he was just one person--and he knew that," Cook said. "It was his selection of people that helped propel the culture."
Cook credits Jobs's vision of the Apple ecosystem, one in which Apple controls the experience from end to end, as the reason for the company's continued success. He pointed to Microsoft and Android as cases where different groups controlling different parts of the product lead to a disjointed and poor experience.
Apple is also willing to sacrifice popular technology like the floppy disk, 30-pin connector, and now multiple ports, all for the sake of driving the company forward. Cook said that philosophy came from Jobs.
"Steve was the best flipper in the world," Cook said. "And it's because he didn't get married to any one position, one view. He was married to the philosophy, the values. The fact that we want to really change the world remains the same."