Pretty good analysis overall, although this part is not true:

> With the exception of the mac pro, Apple's entire lineup uses mobile processors.

In fact their entire desktop lineup now uses desktop-grade CPUs. (except possibly some entry-level iMacs that weren't subject to the recent refresh)

  * iMac Pro: Workstation processor (Xeon)
  * iMac 27": Socketed desktop processor (e.g. Core i9-9900KF in top config)
  * iMac 21": Socketed desktop processor (e.g. Core i7-8700)
  * Mac Mini: Soldered embedded desktop processor (e.g. Core i7-8700B)

Yeah, it looks like they switched over to desktop chips around 2017 (they still use laptop memory though -- except for imac pro).

An i9-9900K has a 95w TDP, but Anandtech puts the real load number at around 170w TDP. I've seen people undervolt these down to around 110-120w in the 4.7GHz range. I imagine Apple's dynamic undervolting and custom motherboard can shave 10% or so off that total while their dynamic undervolting can go much lower with fewer cores and lower frequencies. While even that isn't going to make their tiny cooler keep sustained loads from throttling, it could get much closer.

By "laptop memory" you mean SO-DIMMs; the only significant difference to full-size DIMMs is, well, size. Voltage and frequency tends to be the same, leaving aside extreme overclocker's RAM.

In c't magazine's review of the current iMac, they found that the whole machine appears to have a power limit which is shared by CPU and GPU, so yeah, Apple are definitely doing something fancy in that regard.

You’re talking about mobile here, and I get why—it’s a majority of their computer sales—but most of these arguments don’t apply in the case of the Mac Pro. A Xeon and an Intel mobile processor are different-enough chipsets that there isn’t much motherboard silicon that can be reused between them. (They could maybe reuse the chipset design from the iMac Pro, but Apple kept saying that was a “transitional” design—which I read as “an evolutionary dead-end stop-gap product that we aren’t basing our future design thinking off of.”)

Likewise, I do agree that Apple is likely switching to ARM for mobile—but are there any ARM cores on anyone’s product roadmaps that could power a Mac Pro, or even an iMac? Nah.

I do agree with the greater point: Intel probably do have an exclusivity agreement with Apple right now, and so Apple sticking with them right now isn’t evidence of anything in particular.

But to me, it looks like a natural shift for Apple, in the near future, to adopt a hybrid strategy: if they can switch to ARM entirely for their highest-volume segment (laptops et al), then they’ll no longer need the benefits of having Intel as a locked-in high-volume chip supplier, and will thus free to choose anyone they like for the much-lower-volume segment (desktops/workstations) on a per-machine basis. That might be Intel, or AMD, at any given time. They won’t get such great deals from Intel, but in exchange they can play Intel and AMD off one-another, now that they’re in healthy competition again.

Intel is probably just as aware of what Apple has on its roadmap as Apple is aware of what’s on Intel’s roadmap, so I would expect, if anything, that they’re scrounging desperately around for a mobile architecture that’ll be competitive-enough with the nascent A13 to stave off that collapse of a partnership.

My prediction is that within 5–10 years, we'll be seeing ARM/Apple CPUs at the core of their laptops, low-end desktops, and even their top of the line Mac Pro. Powerful x86 CPUs will be still be available in the Mac Pro and implemented as an "accelerator" card.

another large consideration is availability of chips. Can AMD spin up enough production quickly enough to handle Apple, on top of their own sales, and their soon to be ramp up for new xbox and ps consoles..