It's also a perfect use for local System One models that can classify prompts and forward them to the right module - calculator for math, distrobox for shell commands, LLM for natural language questions and normal search for everything else. Not using a fixed classifier because plugins should be able to add their own question types.
The article mentioned WinFS and relational filesystems. That's another good idea, integrate metadata so you can support use cases like finding all pictures of your dog or all playlists with Ed Sheeran songs (to remove them). Everything bound to the file entries instead of ID3 tags inside the file or app specific databases. It would be a lot more reliable and probably faster.
IIRC bcachefs is already a relational database but I don't know how good the query APIs are. If we can't do full extendable tags then at least add user defined groups/tags like Work and Games and Photos to make finding things easier. People remember what a file is better than where it's stored.