Samsung makes fast expensive storage but even cheap storage can max out SATA, hence there's no point Samsung trying to compete in the dwindling SATA space.
replies(1):
You could even get more using a PCIe NVME expansion card, since it's all over PCIe anyways.
You can buy cheap add-in cards to use PCIe slots as M.2 slots, too.
If you need even more slots, there are add-in cards with PCIe switches which allow you to install 10+ M.2 drives into a single M.2 slot.
More so it would only need one drive. ODD is dead for at least 10 years and most people never need another internal drive at all.
And SATA SSDs do make sense, they are significantly more cost effective than NVMe and trivial to expand. Compare the simplicity, ease, and cost of building an array/pool of many disks comprised of either 2.5" SATA SSDs or M.2 NVMe and get back to me when you have a solution that can scale to 8, 14, or 60 disks as easily and cheaply as the SATA option can. There are many cases where the performance of SSDs going over ACHI (or SAS) is plenty and you don't need to pay the cost of going to full-on PCIe lanes per disk.
E.g. going to the suggested U.2 is still going to net you looking for the PCIe lanes to be available for it.
That doesn't seem to be what the vendors think, and they're probably in a better position to know what's selling well and how much it costs to build.
We're probably reaching the point where the up-front costs of qualifying new NAND with old SATA SSD controllers and updating the firmware to properly manage the new NAND is a cost that cannot be recouped by a year or two of sales of an updated SATA SSD.
SATA SSDs are a technological dead end that's no longer economically important for consumer storage or large scale datacenter deployments. The one remaining niche you've pointed to (low-performance storage servers) is not a large enough market to sustain anything like the product ecosystem that existed a decade ago for SATA SSDs.