Of course. Though, Apple is more concerned with besting the prior models than they are with besting the competition. Hence, the asininely vague graphs and comparisons to "the latest/most popular PC chip". If there was a superstar x86-64 CPU that Apple could directly say "look, this outperforms this CPU in every possible way" they'd probably have done so. Instead, it's shrouded in kludgy marketing.
But are they only concerned about beating prior Mac models because that's the only thing relevant to their customers (for which a case could be made; shifting off macOS is hard), or because direct comparisons to the best contemporary PC hardware would be unfavourable? At the end of the day, no one is forcing Apple to include PCs in their graphs - they could just benchmark against the last generation M-series - but they can't really avoid it since Windows dominates the desktop market and the comparison will be made regardless.
There are benchmarks that will show impressive gains. Just as I'm sure that there will be some that don't. Again, Apple is optimizing the performance of these SoCs to specific workloads. It stands to reason that some will be markedly more powerful while others will not.
I guess one has to pay close attention to the benchmarks, and determine whether the specific areas of acceleration align with your needs. If so, then great. I agree that for a video editor, it makes more sense to accelerate video codecs than use a beastly GPU to process video via CUDA.
I think that depends on your workflow. I know that, when Apple was re-evaluating their mistakes with the 2013 Mac Pro, one of the things they realized is that most of their customers actually didn't need multiple GPUs.
A minor point, but in my opinion, the dual-GPU thing in the 2013 MP was dictated by trying to distribute the heat sources, so their sexy cylinder concept would work. I don't believe they started from a position of being convinced of a multi GPU future (why?) and then designed the computer around that. Dual GPUs have never offered any advantage over an equivalently powerful single GPU. They only make sense if you're already running the fastest single GPU (or close to it), and need more of them.
UltraFusion would seem to be vastly preferable from the standpoint of latency between SoC components.
Of course. But unless the SoCs communicate through several hops to other SoCs, also increasing latency, each of the 4 chips would need enough UF connectors to connect directly to the other 3. This essentially means 3 sides of a Max would need UF interfaces - is there room, given RAM channels, I/O etc.? This feature (with all the associated circuitry) would also be wasted in the vast majority of Max installations (MBPs and Max / Ultra Studios), increasing cost for no benefit. Connecting 2 Ultras over a more traditional bus could potentially give significant performance gains over a single Ultra, without wasting excessive die area or requiring a separate Max design for this one application.
Nah. They saw the 24-core CPU, the 60-76 core GPU with 7 Afterburner cards' worth of accelerator performance, and the 64-192GB of RAM and decided that it was enough to suffice for the vast majority of the customers that would need this class of machine. It's not that the Mac Pro isn't important to them. It's that, TO THEM, the Mac Pro does not need to be anything more than an Ultra variant of a Mac Studio with I/O that would only be possible in the configuration of a tower. If Apple did the research and found that most of the people needing to buy a Mac Pro really only needed what this 2023 Mac Pro has to offer, then it was merely a calculated risk as to just how many customers they'd alienate by nixing the added upgradability from the 2019 model.
It's a slightly circular argument though, as what defines a Mac Pro customer? If you release a tower with limited built in GPU and no GPU expansion, you're clearly not going to attract e.g. 3D animators. If you whittle the scope of the product down until it just appeals to video editors, colour graders and so on (as big a market as they may be), is it really a success? Versus a wider market it could have appealed to? Fundamentally, the Mac Pro is built from what Apple have available, which in turn is dictated by the iPhone and laptops, alongside desktops like the iMac, mini and Studio that reuse laptop SoCs.
Even if Apple were interested in the PC workstation market, they are not well placed to compete in it, as doubling up on laptop SoCs only gets you so far. The Max is a balanced chip, with a sensible allocation of CPU to GPU, but to get more GPU requires adding a lot of CPU as well. This would become ridiculous with a 4 way chip, which would have way too many CPU cores, just to get a reasonable GPU.