Talk about data being separate from programs always reminds me what a good job Microsoft did with the spacial filesystem (that means one folder is one window, and they remember their location), single-document interface (a UI paradigm) and COM (a cross-process communication system). As a novice user not understanding a whole lot about the system, your documents were in the operating system and not in a specific program (this still wasn't perfect and a lot of new users did think their documents were in programs, which might be why we gave that up) and those programs could talk to each other and embed each other's documents.
This stuff probably seemed moderately innovative if you didn't grow up with it, seemed blindingly obvious if you did grow up with it, and somehow, like idiots, we've managed to lose it again!
> this still wasn't perfect and a lot of new users did think their documents were in programs, which might be why we gave that up
To this day there exist office workers—ones old enough that no, it's not because the were introduced to computers via smartphones—who use a computer for hours every single weekday day but get totally turned around in a file manager, and don't know even the extreme basics like how to copy and move files.
There are offices full of such folks, in non-tech offices, where the person who knows how to sort-of use a GUI file manager is the "computer whiz" they go to with questions.
The "files and folders" hierarchical tree model for a file system is one where I wonder about the limits or effectiveness of the skeuomorphism approach to convey such a concept. If you're coming from a place where information was generally held and organized on paper, it _should_ be natural that you can group files within a container like a folder, and the kind of folder the iconography showed should be able to contain sub-folders.
While many did pick up on the idea, where were the shortcomings? Were the early graphics not enough to build the mental link. Was it the common grid view of icons. Was it the icon being an abstract thing you needed to open to see the contents instead of looking at it directly (as previews on the icon which came later), was it things opening in separate windows. It's not as though other more visually 'rich' methods to show a file system such as 3D or animated took off.
There's also the modern version that gets brought up occasionally where people who are using devices with mobile instead of desktop OSes apparently don't know how to work with file systems to manage data, and presumably they'd have even less exposure to the physical paper concept that inspired it.
OLE objects are just FAT like filesystems; nothing too disimilar to Unix if it mounted disk images with text files and different images with it in order to create a document format.