What could you possibly delete to get down below that configuration? It's basically a very, very high-end case and power supply (capable of supporting huge expansion) with minimal components. If you run it out of the box, it is not an especially powerful Mac. It underperforms not only any possible iMac Pro, but also a $3000 non-Pro iMac. It's possible to configure a faster MacBook Pro, and to come close with a Mac Mini.
Apple has never sold a "bare-bones" configuration that won't boot and run some reasonable software, on any machine, ever. HP will sell you a Z8 that will barely power on (4-core 1.6 gHz processor and 8 GB of RAM, for example). Apple has sold nonsense configurations of high-end machines that underperform lesser Macs and are meant only for expansion - but this Mac Pro is already that. It's a $6000 computer that performs like a $3000 computer, except that it has tremendous expansion potential.
The only reason to buy a Mac Pro is to expand it well beyond the base configuration in some way or another - the base parts are chosen so they don't actively interfere with using the machine for some task where that part doesn't really matter. The 8 core processor is fast enough for tasks where the real work is on the GPU, the 580x is fast enough to just drive a display for audio work and the like, 32 Gb of RAM is enough for non RAM intensive tasks and the 256 GB SSD is enough for some jobs where the real storage is on another drive. If all four are enough, an iMac is MUCH more economical. If none of the four needs to be more than doubled, and in some cases much more than that, an iMac Pro is a better choice.
The Mac Pro exists for a very specific kind of workload, where some component needs to be expanded to a very high degree. It can support all four expandable components being radically expanded, but it only makes sense if at least one pushes through the boundaries an iMac Pro is capable of. Otherwise, why pay the premium for the Mac Pro over an iMac Pro?
Apple has never been willing to sell configurations of expandable machines that are basically Hackintoshes. If they sold a 4-core, 8 GB version of the Mac Pro, it wouldn't reasonably run Catalina and any significant application. Nobody's going to buy a Mac Pro to run Mail and Word, especially because that's certainly a $4000 computer and probably a $5000 one. A relatively small number of hobbyists (no company would save money that way, given the support implications) would buy it and immediately pop in their own CPU and RAM. HP lets hobbyists do that by selling a Z8 that will barely boot, Apple doesn't.