Why would a Mac Pro need something an iPad or Macbook does not?
Universal Storage is the future, everything soldered and security coded.
Replying to myself here, but as I keep an eye on Apple's Australian store, I note that while the full range of 2019 Mac Pro SSDs are listed, but perpetually sold out, the 2023 Mac Pro no longer has any storage listed as purchasable accessories.
The only available accessories are Wheels, Feet, thunderbolt cables, or a Belkin lock. There's no storage upgrades listed for the Studio, either.
Makes one wonder - what soft of supply chain issues could Apple be having to be unable to keep this stuff in stock, or have they just decided to make storage no longer user-upgradable, by making it a service item only.
I imagine they were getting hammered by people who bought the upgrades, and then found out they needed a second Mac to enable them, and perhaps it was more trouble than it was worth?