Under the hood, iPhone OS is virtually the same as the OS X that runs on Mac desktops. Steve Jobs announced this back in 2007, and it has been confirmed by any number of jailbreaks that allow third parties to explore the iPhone OS from the command line. It may be closed but iPhone OS is still basically OS X.
What differentiates iPhone OS from Mac OS has been the openness of the platform. Developers must go through Apple's review process to deploy software to the vast audience of iPhone OS device owners. Apple sets the rules, ensures the quality, polices the system. It's a new way of computing, closer to the TiVo or Wii experience than, say, the Windows or Linux experience.
Could it be the future of a new Macintosh line?
It's all about the numbers. With successes like this, Apple would be foolish not to even consider an "appliance" computer system running a closed version of OS X. I'm not suggesting that Apple would drop traditional OS X systems. After all, people still need development computers and production-quality computers. But consider how many people currently purchase iMacs and Mac Books, who generally do not need much in the way of advanced features. How many of them might benefit from a desktop system that's more iPad-like than iMac-like?
A closed desktop Mac would have to offer a lot more computing flexibility than the iPad offers. It would have to support mouse and keyboard interaction, better multitasking, and the ability to do business-quality work like accounting, document preparation, image editing, and so forth. And yet, you could imagine Apple preparing an OS and software that addresses these needs using a richer version of the iPhone OS frameworks, stepping outside of the current OS X evolutionary path.
If there's any point to this little post, it's this. Apple has entered into its most successful period by providing devices that work with the tasks that people want to experience on the go, whether it's making calls, checking location-based resources or handling e-mail and surfing the web. I wouldn't be surprised if Apple took that same highly-focused, user experience-centered design and migrated it back to the desktop.
What do you think? Could a closed OS X desktop be part of Apple's future? Let us know in the comments.