If Intel knows what they are doing, then why is Qualcomm killing them in the mobile space? Why was Broadwell delayed for so long? I don't think Intel is as steady as you think. Anyone that understands Apple knows that they would drop their reliance on a 3rd party as soon as possible, including Intel. You do realize that Intel is the only reason new MacBook Pros and iMacs haven't been released already? Apple HATES that. They will shift to ARM as soon as it will be accepted in the market.
I think it's gonna take some years for the complete switch but that's their ultimate goal in my opinion.
Apple is more attracted to the consumer world, of course, and the future of Macbook is ARM like the iPad.
The two worlds, iOS and OS X will continue to exist, but in the future I see apps able to adapt to the OS so with the same project (maybe compiling different binaries) you will be able to create an app for the iPad and the Mac. Different UI for touch and mouse, but same core functions due to the same language and many shared APIs.
It could be possibile with Intel, but more likely they'll control the CPU on the Mac as well.
I don't know if the PRO users will like that move, but let's face the fact they're a small percentage of Apple's business now so I'm afraid Apple doesn't really care about them like it did in the past