If you check out the official iPhone site you will see that it declares:
“All the power and sophistication of the world’s most advanced operating system — OS X — is now available on a small, handheld device that gives you access to true desktop-class applications and software”
So unsurprisingly, many people have become pretty confused. You can imagine some people genuinely wondering if it will run the full versions of Photoshop or Final Cut Pro, or any of the other massive desktop apps they use. (Of course it wont).
So why didn’t Apple give the mobile version of their OS a slightly different name, like “Mobile OS X”? This way, instead of confusing people, they’d put across the message that it’s “Same, same but different“.