They never said that they would release the Mac Pro next year (2018) they said “not this year” (2017). From the link you posted...

These next-gen Mac Pros and pro displays “will not ship this year”. (I hope that means “next year”, but all Apple said was “not this year”.) In the meantime

Oh, you're so right! I mis-remembered and didn't bother to check through the article first. My mistake. (I knew the article from reading it when it was published.)

Still, I'd be surprised if they expected it to be any later than 2019. Historically they never give information out like that early at all, so for them to break precedent and announce anything seems to indicate that they're fairly confident. Hopefully it goes better than AirPower haha.

Just the opposite. All indications are that they hadn’t even started on the Mac Pro when they made the announcement, their way forward before then was the iMac Pro. I doubt they had any game plan at the time.

From what I've heard -- although my "little birdies" are probably much less reliable than Gruber's -- they had technically started on the Mac Pro when they made the announcement. But you're only off by a matter of weeks.

That would have to sting.

At that point the Mac Pro will have been _over five years_ since its last update (December 2013).

Of course Apple is still gleefully charging full price for Ivy Bridge (Xeon v2) processors, not to mention ~$600 for 32GB memory.

That has to sting.

Apple admitted they made a design mistake with the Mac Pro. It’s clear that they were originally planning to abandon the Mac Pro and release the iMac Pro to address the high end - along with operating system changes so Macs would work better with external GPUs.

Then they had an about face mid last year.

What I don’t understand is how hard is it for them to make a simple pro Mac in a tower case? I doubt that it takes PC manufacturers two years to design a mid tower high end workstation. Intel is doing most of the engineering and they (Apple) already have a very high performing SSD controller.

I'm not sure if those examples are really the same as AirPower? I think AirPower is the first major unforced consumer pre-announcement SNAFU Apple has had in a long time, and the pro situation is different. It came up in a previous thread but the last really major one that instantly came to mind was during the Steve-era with the G5, where he got up and promised it'd hit 3 GHz within 12 months and then that never happened (and he was reportedly furious about that). AirPower really was somebody getting carried away. Although it does at least serve as a hard demonstration that Apple's secrecy is more then just a PR hype thing, not announcing a product until it's going to mass manufacturing helps prevent a lot of angst over the inevitable unknown unknowns hit pursuing aggressive engineering.

The Pro systems in contrast:

>In the last year or two they've broken precedent and announced a few things prematurely[...]iMac Pro/Mac Pro

The thing is they basically had to do this if they didn't want to just dump the desktop pro market entirely (which perhaps was a source of internal debate, but apparently they decided it actually was something they cared about). The real tower Mac Pro was 7 years old. The obvious-failure-on-launch cylinder Mac "Pro" (with its 450W budget) had as expected never been touched again, had effectively zero 3rd party support due to fundamentally bad design decisions, and could even be outperformed in some roles by its predecessor. Professionals in that particular market were (and are) dumping Apple, mostly wholesale for modern PC systems though some may have gone hackintosh (VMs interest me in that role personally). At any rate the situation was untenable and Apple had no actual hardware whatsoever on hand to offer either.

So they had to either just decide Mac pro desktops were not valuable and declare it dead and done, or if it was valuable to offer any remaining users there some reason (however delayed) to not completely give up on Apple. The only card they really had to play is to make a future promise in a way that they normally do not. I don't know how well it worked overall, and I'm highly pessimistic that Apple actually learned a lesson there and is doing something that could be interesting and worth it (though FWIW there at least in principle is cool stuff Apple could do there), but that seems to be how it worked out. I don't think it was due to some long term change of strategy or Apple getting over excited, it was simply the only move remaining to them after a fairly bad set of own-goals if they wanted to continue to exist in that space.

And if they do manage to find their legs there again I wouldn't be surprised if this was a one-off and they went right back to staying quiet while doing yearly bumps rather then any sort of roadmap. Though organization structure changes would be more reassuring there.