Sure, but that SGI machine, if it was real, was a lot of bespoke hardware plenty capable than anything you could buy off the shelf elsewhere. The new Mac Pro on the other hand doesn't have anything of significance, outside of the OS at least, that isn't completely off-the-shelf hardware.
It's really just an off-the-shelf CPU, and RAM, a PCIe SSD only so bespoke that you can't save money by literally buying replacement and upgrade parts off the shelf, a set of GPUs that again are only so bespoke that you can't save by buying them literally off the shelf in a somewhat off-the-wall case.
SGI workstations from back then came with bespoke CPUs, GPUs and a whole lot of other things with very large development costs. Those machines absolutely had some major development costs to recoup to develop all of that bespoke hardware. All of the genuinely expensive-to-develop components on the Mac Pro are completely off-the-shelf and available to Apple for not much more than the cost of manufacturing said components.
My machine at work (Ryzen Threadripper box with 64GB of ECC DDR4 RAM, Quadro RTX 6000 and 4000 GPUs, 2TB 970 Evo Plus SSD, etc.) basically kicks it's ass in just about every aspect and is cheaper too as soon as you begin bumping up the Mac Pro from it's paltry base spec (8 core CPU, single RX 580 GPU, 32GB of RAM and a 256 GB SSD).