Apple is a trillion dollar company. Their schtick might be making slick technology, but their driving purpose is making money, and they are exceptionally, superlatively good at making money. Apple is not as good at making computers as they are at making money, which is not to say their computers are bad, per se; they're just that good at making money.
The whole "ecosystem" thing certainly has a lot of easily-touted and more-or-less legit consumer benefits, but the value to Apple is in cranking up the odds that customers buy more Apple products. Is the money-gobbling corporate juggernaut going to sell the best possible computer, that users can optimize by buying other companies' stuff, or develop an intriguing, niche alternative that locks in deep-pocketed users?
It's not a coincidence or scheduling fluke that Bob Iger came on stage. That was a show for all the shareholders and creative execs out there. There is now the impression, regardless of how accurate it is, that the most valuable entertainment brand in history does its tech stuff with Apple products. You want to make a billion dollars? Better listen to Cook and Iger! Other execs who are more focused on market perception and making money than understanding tech are going to buy Mac Pros by the pallet. Will all their devs/techs/artists be happy? Maybe (they're still beastly systems). Will it be a smart investment? Very maybe (abysmal upgradeability). Will Apple have accomplished their goal? Yep (Capitalism, baby!).
Sure, there are companies (and individuals) out there that need to customize some absolutely monster rigs, and CTOs who do understand their own highly specific computing needs, but Apple simply isn't in the business of making components for custom supercomputers that can model the atoms in a nuclear explosion or global weather patterns or whatever. If your AI research requires Nvidia GPU architecture and TBs of RAM, Apple isn't shunning you; they're just tacitly acknowledging they aren't trying to seriously move on the current ML market with their system architecture.
Bottom line, you don't have to like what Apple is doing with the Mac Pro, but it's just silly to say they are messing up. They know what they are doing. Their strategy is very clear. They want to make every part of the products they sell and appeal to the premium/luxury market. This has worked extraordinarily well for them, by the metrics that matter to them, and this is not a huge deviation from that winning strategy.
