The iMac Pro's place was, from the day it was announced, on shaky ground. It was a relic from (https://sixcolors.com/post/2021/03/goodbye-parallel-timeline-apple-discontinues-the-imac-pro/ (as Jason Snell puts it)) "a parallel timeline", where Apple didn't decide in early 2017 to rededicate itself to its professional users. It was an undeniably great machine, its cooling system a work of art, but it was conceived in a world where it replaced the Mac Pro, and once Apple decided to revive the Mac Pro, it was always questionable whether the iMac Pro would hold a permanent place in the product lineup. When it never received a meaningful update over the years, today's news seemed inevitable.
That said, it's very much the second shoe to drop this week. I'm still trying to figure out what the combined stories mean, in the near term. Does the elimination of the BTO storage configs of the 4k iMac mean that Apple has all it needs of the standard configs for the foreseeable future, and it's converting a manufacturing facility? Why isn't the 4k tagged as "discontinued" like the iMac Pro? Are the standard configs sticking around after an Apple Silicon replacement arrives? If so, it looks like the opposite tack of the Mac mini, where the high end Intel configs stuck around - elimination of some of the expensive Intel options points to something coming into the lineup above them, but that would also seem to indicate something other than an M1-based machine, given the existing RAM limitation.
Then there's the fact that the high-end Intel storage options are gone, but you're still free to upgrade to an i7 with 32GB of RAM and the Vega 20 GPU, but wouldn't anybody interested in those upgrades also want something other than a 256GB SSD or 1TB Fusion Drive? It's all a bit mysterious.
Here's hoping we know more within the next month.