Apple is going to hurt Intel the most going forward. The way these guys have been improving performance on the Ax SoCs is frightening. Intel's tick tock model is history and Apple's tock tock model is the future. Apple has been adding 10% IPC every year to the Cyclone core from A7->A8->A9. The move to FINFET in A9 gave a huge clock speed jump too. Apple iPad Pro with A9X is going to take sales away from Wintel 2-in-1s. Going forward I expect Apple to move all their products to ARMv8. I think Apple might design 2 versions of their custom ARMv8 core - a high performance version for workstations, desktops and high end notebooks which can hit 4+ Ghz frequencies and a low power version which is used in tablets, phone and ultrathin notebooks. The low power version will use high density libraries and the high performance version will use high performance libraries and be targetted at maximum performance. Its not a question of will they but a matter of when ? I think sometime in 2016 or 2017 we could see this happen.
I agree with much of what you had to say, but this paragraph kinda fell off the wagon. The Mac volume isn't enough to justify the expense of another chip design team. The reason they can throw so much money at the mobile SOC's is the volume they sell.
If they were to go ARM in their computers, then they'd lose (Wild guesstimate here) 30 to 40% of their Mac sales, by losing Windows compatibility.
To keep that loss from happening, it'd have to be able to emulate x86 very well. Apple is probably better than that than most, as they have gone through several ISA changes since 1984. But, you have to have a huge jump in CPU power to do so. If they, for the sake of conversation managed to get twice the raw CPU power that Intel gets, then yeah. You could at that point make the jump.
As good as they are with their ARM cores, they aren't ever going to get twice the performance Intel gets. If nothing else though, they seem to be the only one who has the ability to push Intel, now that AMD is nothing more than a blip.
P.S. I do hope the AMD Zen does well. It's not healthy for the industry to have a sole source, proprietary product for most of the worlds PC's, servers etc.
This isn't a bash on Intel's ability, they have some great engineers. And if they were to enter the mobile market via ARM I'd cheer them on, as they could likely do very well.