Similar prices to what SATA SSD's were originally.
This too will come down eventually.
Well, it was a given that NVMe would come down, because the only real difference between that and SATA is the controller. Plus, M.2 drives avoid the added cost of a case. Yet, the fastest NAND-based NVMe drives will continue to command a premium, since they'll use lower-density NAND to get better performance.
However, you're assuming that 3D XPoint will follow the same price curve as NAND, and I don't know if that's true. If we look at how NAND got cheap, it's because:
- Manufacturing node shrinks
- Packing multiple bits (now up to 16, with some talking about 32) per cell
- 3D stacking
As for #1, presumably 3D XPoint is made on a somewhat comparable node to recent NAND. Maybe previous-gen, but suffice to say that it's not starting from way behind, so it doesn't have much room to catch up, here.
Regarding #2, I don't know if 3D XPoint can manage the same trick, but it doesn't sound like it.
So, that leaves #3. We'll have to see how well it can live up to its name and the supposed promise of being 3D, but I think the first gen chips were planar.
In conclusion, if they can't pack multiple bits per cell, then it's going to need density improvements from stacking and areal density, in order to compete with NAND. I don't know how much potential there is for either, but it's probably not a stretch to say it's not likely ever to compete with NAND on price. What we'll probably see is a world where HDDs continue offer the best GB/$, 3D XPoint offers the best performance, and NAND sits somewhere in between.