> I realized something that bugged me. ELF is already a database.

Even more broadly applied: Every base of data is already a database (that's what the compound word means). Programs like sqlite and postgres used to be called by the more precise term "Relational Data Base Management Software" or "RDBMS" until their use became so widespread that they were colloquially called databases instead.

The very first data base structures were more like, each geometric sector of a hard drive is a record, and each head is a column. This was a straightforward translation of punch-card workflow onto a magnetic disk.