What about the converse question? Why does the filesystem not provide indexing, tabulation, relationships among document, archival tools, tools for merging two diverged versions of a folder tree, etc.? (Is there one that does it? I don't know!). E.g. Why can't I store a slidedeck by slides and show a "document" that is composed of transcluded bits and pieces? I think pondering alternate systems from time to time is valuable.