Vendors in the NAND fabrication are still facing a long term glut in the market. This has driven chip prices to test new lows almost every week. Earlier an Android tablet for $79 with 512GB of NAND shows how low the prices have come. Such low prices will likely pressure Apple to bump up capacity in entry level phones and iPads.
The M.2 situation is also driven by intense competition in the performance market as well as in the bulk capacity market. The Intel 665p 2TB SSD has taken over the role of the 2TB hard disk that was powering the old AM3 machine several years ago.
Even with increased sales of laptops the glut of NAND has persisted. This has also driven SATA SSD prices lower which has pressured low capacity hard disks almost out of existence.
Kioxia and WD have come up with a new BiCS 3D NAND technology, with 162-layers and a 40 per cent smaller die. The new technology can get about 70% more bits per wafer. This will help bolster the capacity of devices in later 2021. SK hynix revealed a roadmap to 500+ and even 800+ layers in August 2019. Other suppliers are thought to have similar internal roadmaps.
The Intel 670p SSD should be available relatively soon but Intel has not updated their 6 series website yet. Intel has the 760p TLC SSD which is a higher performance product in the premium market. So far no news since the press release last December. Higher capacity SSD are ideal for growing game collections.
Most consumer gaming motherboards have dual M.2 slot. SATA SSD typically have space for 16 NAND chips so 8TB units are not hyper expensive. Controller limitations prevent the manufacture of larger capacity products. New controller logic is needed to overcome the latest capacity wall. Psion is the current vendor but even the latest E18 device is still capped.