I don’t think you’re wrong, yes all the individual technologies in the iPhone already existed, but there’s a bigger picture. The fact is the iPhone revolutionised hand held mobile computing, so given that fact it’s up to us to figure out how they did it and why it worked.

The reason Apple’s success at product development is so hard is that it involves orchestrating many, many different technologies together to create a powerful set of capabilities accessed through a consistent seamless user experience. That’s not a simple thing to even describe or discuss, let alone understand. It’s why they take years to develop products, and are almost never first in a new category, such as smart watches as you say.