Well, thank God you're here to tell the rest of us how dumb we are, having opinions and all.
This isn't about opinions. It is about the facts.
Fact: Apple has cancelled XGrid.
"XGrid Officially Dead"
https://forums.macrumors.com/threads/1412900/
So the likelihood that this is some magical glue that is going to make these ARM solutions relevant is
deeply lacking in substance. Apple has already explicitly told folks they don't want to do XGrid like things. To couch that as being a difference of opinion is pure misdirection.
They are OK with someone else perhaps putting something like this together ( e.g., probably would not be adverse to Intel rolling out drivers to their Phi card and making their parallel compiler toolstack work on OS X. ) But as far as that being an "Apple driven" solution... no.
Fact: Name one current or proposed Apple iOS device with no screen output?
Crickets chirping.........
This is not a matter of opinion. iOS as a computational module OS kernel? Why? It is not an opinion that this is not even remotely motivated at all. This is not "think different". It is pull random stuff out the butt.
The primary purpose of iOS is to be a touch GUI oriented OS. It makes some sense to use it on AppleTV as there is still a GUI and large TV buttons to push by remote control. Even a watch running mini apps with possibly touch/voice/button control. But no GUI at all?
Apple Airport router products don't. No GUI. No iOS.
Fact: Apple is not a "I have a hammer so everything is a nail" company.
Massive Apple data centers don't run OS X. They certainly don't run iOS. Right tool, right job. Apple probably will have some ARM cores doing VM duty running front end web infrastructure at some point. Could it be custom boards? Sure google , Facebook and others build/commission custom boards for substantive numbers of their grid computation nodes. Do most of them sell them? No. Would Apple likely sell theirs? No. More than likely would buy "off the shelf" solutions; just like they do now.
"Apple designs some ARM SoC so therefore it has to go into Mac Pro somehow" is a "hammer / nail" , "round peg / square hole" groundless speculation. It is not oriented to solving problems that Mac Pro users have. It is a solution in search of a problem. It is actually far more indicative of thinking inside the box; not outside of it.
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I just wonder if the 2013 MacPro CPU chip is "hand waving" since it has not been released yet.
The most likely candidate Xeon E5 was announced/released a year ago. So no it isn't. If Apple shipped next Tuesday most likely it would be something that has been shipping and/or announced for almost a year.
Even Xeon E5 v2 (Ivy Bridge) engineering samples have been floating around for a year at this point.
http://news.softpedia.com/news/10-Core-Intel-Ivy-Bridge-EP-CPU-Has-95W-TDP-at-2-4GHz-245709.shtml