Daring Fireball: The Tablet

Apple is not in the business of making monolithic OSes that they cram down your throat on as many widely-varying devices as possible. Apple is in the business of making complete products, for which they craft derivative OSes to fit each product. There is a shared core OS. There is not a shared core UI
via daringfireball.net

That's why we'll never see OSX being released for non-Apple hardware.