I think Apple pretty much have to announce the Mac Pro at WWDC, even if it is just a preview. They’re not obliged to “complete the transition in (exactly) 2 years” but it would start to look like carelessness otherwise, and the target users really need some sort of roadmap - £20,000 workstations are not “impulse purchases”.
Apple didn't "have to" in 2017 when they didn't formally announce or ship anything. They didn't "have to" in 2018 when they didn't formally announce or ship anything.
June WWDC 2022 is't particularly any significantly different from those situations. They would need a better hint than a simplistic "another day". ( In 2018 they threw out "not this year". Not overly specific either, but an adjustment on expectations. ).
Apple could easily do an announcement in October when macOS releases and there is some more Macs to do.
The more critical issue is whether it is ready to ship in next 6 months or not. If not then there is no reason to announce. I think many folks are presuming that it has to be already done a while ago and the supply chain for components is solidity producing soon. If production is ready to go in a handful of months , then yes they should give some lead time , but "WWDC 2022" isn't the "have to" factor there.
3 months ago there was talk of an iMac Pro that Apple was going to "have to" announce this Spring. And now there isn't.
There are several ways the Mac Pro could go - one is some sort of scalable system using multiple Mx SoCs using something like NUMA, which could conceivably launch with M1 Ultra, without Apple technically making another M1 variant. My money is still on this idea because of the economies of scale vs. making a whole new SoC -or even die- for Apple’s smallest selling system.
There is no physical adapter/connector on an Ultra to do NUMA with another separate chip package with. It is like doing NUMA with no Infinity Fabric or QPI on. AMD/Intel. Or using a Ethernet cable when there is no Ethernet controller in a system.
The other major issue that macOS doesn't deal with with relatively high levels of "Non uniform access" of memory.
With M1 generation and macOS Apple has neither the hardware or software tools to implement this.
Then there’s the 4xM1 Max idea, which was a pretty strong rumour for a while, although it seems to have fallen out of favour now people have actually got a look at the M1 Ultra. Apart from anything else, chip design technicalities aside, I’m getting a strong “diminishing returns” vibe from the M1 Ultra reviews, so a 4x variant may be a solution looking for a problem.
If someone has an old 64 bit app with OpenGL 3.0 only utiliize and throws it at a W6800X MPX module are they going to get optimal utilization out of that app on that hardware? Probably not. New GPU , not so new software ... non optimal reasons. Happens all the time on macOS , Windows, Linux , etc.
Back in December 2021 the Informatoin talked about
" ...
The 3nm chips are reported to have up to four dies with up to 40 CPU cores per chip. So they should have no trouble outperforming the upcoming M2 chips. In comparison, the M1 Pro chip uses 8 to 10 cores and the M1 Max uses 14 to 16 cores.
The M3 chip (as it’s currently called) should offer faster speeds and better battery efficiency than the M1 Pro and M1 Max chips — both of which already have impressive performance. Since the M3 reportedly won’t go into production until the end of 2022, we likely won’t see it debut in Mac devices until 2023. ... "
TSMC's pilot production of Apple 3nm chips is tipped to start late 2022 — here's what that means for Macs
www.tomsguide.com
That is not a "ship new Mac Pro fast" solution. Which is why some folks are tossing it aside. Because Apple "has to announce" real soon.
Waiting for TSMC N3 makes the "Max class" dies smaller (if don't crank up core counts a lot) which will make packaging four of them more tractable.