Granted experience in building is required but not that too far out of reach. The new performance model boards, cpus, and video cards(mid to high end) all have that in mind with AI tools, overdrive, and ocing capablity.
The Blackbird offers a degree more flexibility for choosing from a larger list of options compared the typical prebuilds. But you still pay through the nose for seeing just that.
As far as the case by itself people custom manufacture their own cases having worked with materials like a machinist/tool+die, wood working, etc. pccupationally. Then add a little practical experience in choosing hardwares for gaming builds and there you have it. Support? Custom builders get support for each item separately anyways.