It probably would have been easier to start the iMac Pro series in 2013... rather than spend time on the whole new trashcan Mac Pro (with all its problems)
Someone correct me, but I recall one of the in-depth looks at the iMac Pro more or less painted it as largely a re-organisation of the same basic internals as those in the 2013 - there's a lot less "new" development in that machine, and a lot more "build it from the parts bin" than is generally marketed.
Since Apple is a one-stop shop... you rely on them (and only them) to provide the software and the hardware. But lately the hardware is an issue.
For example, I'm a pissed off former / current Aperture user - my next photo migration will be to Capture One, or Affinity's DAM or Skylum's Luminar DAM, all of which are cross platform. Why would I buy a mac - literally the only thing I can think of is Airdrop from my iOS devices, but maybe I'd just get the cheapest mabook, or a mini for that, and just use it as a dumb airdrop receiver to a shared folder on my network, that could be accessible from a shared folder on a PC workstation.
There's a house of cards, insofar as unless you're using FCPX or Logic, most everything else is cross platform already, and probably in the Pro context, you're not interacting with the parts of the Mac experience that are the thing that makes the Mac "nicer"
This gets even more apparent when you get into VR where nothing of the user experience is furnished by the host OS, (which I know I've probably been an insufferable born-again about on here of late - hey, when you get the holy fire...) but which I honestly believe represents an existential threat to the future of the Mac as a creative desktop computing platform, because creative apps that use a flat 2d screen as a UI paradigm are going to be a legacy environment, one that iOS will eat. And until such time as GPUs can create a reality indistinguishable from the real world, rapid replacement of GPUs is going to be the defining characteristic of a non-legacy "pro" desktop system.
If it's true that Apple is only offering this supposed "modular Mac Pro" as a last-ditch effort... is this really a platform and company you can trust?
If it has standard retail-upgradable GPUs from both team red and team green, at least two so that for VR they can make a turnkey dedicated GPU per eye the differentiated factor, then yes.
If they're going to do their usual strategy, which is to design things with a primary goal of reducing the risk that an older system could compete with a newer system (eg making eGPU a TB3-supported exclusive to age out the older systems), and make it a sealed box that has no ability for the customer to take it on a route that suits themselves, even if that's contrary to Apple's larger corporate goals, then no. They've burned up too much good will (eg Macbook Pro) by raising prices to give Pros things they don't want, while refusing to make the compromises (thicker body, for larger batteries, a more reliable keyboard and non-soldierd ram) to give them the things they do
Meanwhile... I think we can all assume that HP will update the Z-series next year... and the year after that. Or at least offer something comparable.
The new z4 packs a config with a core i9 and dual PCI3x16 slots, plus a couple of x8 slots. That's a super, super sweet spot for a huge part of the creative market that doesn't need Xeons, assuming the power supply and space constraints can feed a pair of dual 8 pin GPUs.
I for one fanaticise about some bolshie European competition regulator handing out an edict that OS makers must be required to offer their operating systems, and the low level source for compatibility purposes, to any systems maker who wants it, under FRAND licencing terms.