I keep saying it, but I fully expect things to be different with M3. We might finally see the M3 Extreme.
Except... a M2 Extreme would have had 48 CPU cores and 384GB RAM. M3 Extreme
might up that to - what - 512GB RAM? It will still be limited by how many LPDDR packages will fit on/around the SoC dies - and there's still a topological mystery as to how the ultrafusion link will expand to 4 dies
and leave space around them for RAM connections. The number of PCIe lanes won't necessarily change - 16 per die (with the first die's 16 used for the Apple SSDs and on-board peripherals) so 48 (still less than the 2019 MP but, of course PCIe4). Maybe the M3 will get PCIe 5... Or maybe M3 will be little more than the M2 designs with the minimum of changes needed to build them using 3nm technology.
Meanwhile the
competition is already offering 64 cores, 2TB of RAM, 128 lanes of PCIe
plus established support for those pesky NVIDIA and AMD GPUs that every True Pro seems to want, but which won't happen on Mac until Apple U-turns on their Apple Silicon GPU only policy
and buries the hatchet with NVIDIA.
Basically
Apple just don't have a horse in the high-end workstation CPU race and even gluing 4 MacBook Pro CPUs together won't solve that. Pre Apple Silicon, they could buy one from Intel. Now they'd have to design a whole new die - an expensive undertaking - that U-turned on the Apple Silicon principles of unified RAM and integrated Graphics/Media/Neural processors, just for a small and shrinking niche who need high-end GPU and massive RAM for MacOS-only workflows.
Where are they going to focus their design effort - adding more PCIe lanes for the Mac Pro niche which will sit unused on every other Mac, or, maybe, squeezing in another core or two for the MacBook Pro market which shifts an order of magnitude more units? Apple Silicon is a
great product for everything from the iPad through the studio (and the iGoggles of course) - but if you want a high-end workstation it just isn't the tool for the job.
There was clearly a modest market for a Studio Ultra with Slots
which Apple could satisfy with minimal R&D costs, recycling the 2019 case (which was probably the most expensive part of the MP to design and tool up for). The so-called "scam" of 16 PCIe 4 lanes shared between 8 slots is actually a hefty upgrade from what external TB-to-PCIe cages offer. Yeah, I think that maybe they should have called it the "Studio Tower" or something rather than try and pass it off as a successor to the Mac Pro - but my surprise is that they even bothered, not that they didn't whip out a magic new Threadripper-killer as "one more thing".