It's the end of an era.
It's the end of an era.
If you care even remotely about speed, you'll get an NVMe drive. If you're a data hoarder who wants to connect 50 drives, you'll go for spinning rust. Enterprise will go for U.3.
So what's left? An upgrade for grandma's 15-year-old desktop? A borderline-scammy pre-built machine where the listed spec is "1TB SSD" and they used the absolute cheapest drive they can find? Maybe a boot drive for some VM host?
Actually that's a really common use - I've bought a half dozen or so Dell rack mount servers in the last 5 years or so, and work with folks who buy orders of magnitude more, and we all spec RAID0 SATA boot drives. If SATA goes away, I think you'll find low-capacity SAS drives filling that niche.
I highly doubt you'll find M.2 drives filling that niche, either. 2.5" drives can be replaced without opening the machine, too, which is a major win - every time you pull the machine out on its rails and pop the top is another opportunity for cables to come out or other things to go wrong.