And you obviously haven't spend a single minute in the Mac Pro forums, apparently. As a reminder, we went over 2,000 DAYS between the 6,1 & the 7,1.
We still have people upgrading Mac Pros that are almost old enough to vote.
All of the original cheesegraters were very easy to upgrade and future proof.
Look at my sig - that was the configuration of my last Mac Pro when I decommissioned it. And I moved 2 of those cards over to my current Ryzen box.
I ran that cheesegrater for 9 years; I replaced the CPUs, the GPUs (three times), upgraded the optical drive, replaced all of the hard drives (twice), and filled all of the PCIe slots. Two of those PCIe cards have since transitioned to my current computer.