> automated tiered storage. I've wanted this ever since I got an SSD more than 10 years ago, but filesystems move slow.

You were not alone. However, things changed, namely SSD continued to become cheaper and grew in capacity. I'd think most active data is these days on SSDs (certainly in most desktops, most servers which aren't explicit file or DB servers and all mobile and embedded devices), the role of spinning rust being more and more archiving (if found in a system at all).

Tiering didn't go away with the migration to all-SSD storage. It just got somewhat hidden. All consumer SSDs are doing tiered storage within the drive, using drive-specific heuristics that are completely undocumented, and host software rarely if ever makes use of features that exist to provide hints to the SSD to allow its tiering/caching to be more intelligent. In the server space, most SSDs aren't doing this kind of caching, but it's definitely not unheard-of.

Yeah, for enterprise where you can have dedicated machines for single use (and $) there probably isn't much appeal. That's why I emphasized as a home user, where all my machines are running various applications.

Also for video games, where performance matters, game sizes are huge, and it's nice to have a bunch of games installed.

Until $/GB drops to comparable to HDDs, large-scale storage will continue to use HDDs.