The status of US manufacturing in general and Apple's partner plant in Austin is part of the equation. That said, which scenario do those facts support:
1) Discontinuation of the MacPro
2) Moving manufacture back to Asia
3) Building the nMP 7,1 in the USA to create political good will
Depending on the angle you choose, I think you could support all of the above from the same data points. I would add that the 3 year+ holding pattern can be viewed through different lenses as well.
Since I would love to see new computer hardware be more efficient and quieter, I appreciate the concept of the nMP form factor. I'd like to think that Apple expected to have die shrunk parts available by now that would have rendered the size and TDP limitations of the small cylinder moot. IMO, they overshot their target. If they had made the cylinder tall enough to host standard PCIe cards, put in a 650W PSU and offered a super-cooler pad for it to sit on for heavy duty use cases they might have had a winner. Sure, a lot of us need more than 2 internal PCIe slots, etc - but the percentage of use cases that needed more total grunt than the "tall can" form factor could support would have been substantially less than the cohort of underserved pros defecting to Windows/Linux from the 6,1.
Call me wildly optimistic if you want, but here's what I'm hoping:
Apple waits for die shrunk chips that can fit into the TDP envelope of the current cylinder design, then releases the best performance per watt workstation on the market. Iterative improvements in cooling design make thermal throttling of the GPUs rarely necessary. Apple gets serious about supporting eGPU over TB3, including proper drivers for nVidia GPUs. This actually happens before my cMP dies or gets left behind