I think we're heading for a single powerful ARM-based OS that can run on all devices: phones, tablets, laptops, and desktops. Apple can drop Intel and take full control of developments.
The claim that ARM chips can't match or beat x86 chips is nonsense. Apple doesn't need years to catch up: the know-how and technology exists today. Just a matter of technical refinement and commercial judgement.
Spent the last week on a series of lectures in London. Saw thousands of students and walked past a ton of coffee shops and eateries where people were pounding away at their devices. Most people were using laptops or phones. Only saw a small number of tablets. Of the laptops, phones, and tablets, virtually all of them were Apple devices. Perhaps ten Windows laptops at most. There is no meaningful future for Windows products.
For me, a laptop and phone are the perfect working combo. I have an iPad, but won't replace it when it dies. I don't care if the laptop runs OS X or iOS, I just want the laptop form factor and the functionality of OS X. If iOS can be made to match OS X, that'll be fine by me. Don't want legacy x86 software, and certainly no need or desire to ever run Windows or Office.
Don't want a touchscreen device with an add-on keyboard. If using the device like a laptop, navigation is too hard and slow without a trackpad or mouse; and the screen is a pain to use ergonomically, and a pain to see with all the finger smudges.
A tablet with a keyboard is a sudo-laptop. iPads (and especially iPad Pros) are already a two-in-one converged devices: with keyboards, they are sudo-laptops; and without a keyboards, they are tablets.
Maybe OS X and iOS won't be converged as such. Perhaps one will be dropped entirely, or they will both be replaced with a new hybrid iOSX.