Actually Microsoft tried this idea themselves with WinFS. It was planned for Vista but eventually the project was stopped because it was too much effort. I could imagine this to be really useful if it was possible to add arbitrary custom attributes.
http://hal2020.com/2013/02/14/winfs-integratedunified-storag...
There's no sense storing videos, baby photos and "quarterly report new (2) backup newest 08.2019_john.xlsx" in a database.
I was looking forward to seeing it in action based on reports of what it was.
WinFS imposed all of those things and the associated overheads and much, much more every time you accessed anything.
Ever heard of Oracle Database Filesystem (DBFS)?
https://docs.oracle.com/en/database/oracle/oracle-database/1...