Jim Dalrymple on the idea that Apple is trying to create a single OS for multiple devices.
This just isn’t what’s happening. Microsoft is trying to shoehorn one operating system into the desktop and mobile spaces, but that will ultimately fail. They are different platforms and should be treated differently.
This idea likely started because Apple has slowly begun bringing features from the iPhone and iPad back to the Mac. Recently, they even dropped Mac from Mac OS X.
Dalrymple nails it though. Apple will continue to make platform-specific operating systems. Their motivation is to incorporate familiar features of each device. The underlying topic of those features is iCloud. In short, Apple is merely trying to enhance the iCloud experience across their entire product line.
As to dropping Mac from Mac OS X. That simply reduces the redundancy. “Hey look at my Mac running Mac OS X” sounds goofier than “Hey look at my Mac running OS X.” It is the same reason they changed iPhone OS to iOS.