Imagine asking the typical office worker to come up with a way to categorize random books. Don't let them use the Dewey Decimal System[tm]. In fact look at DDS itself: no hierarchy. And the only way librarys could index anything pre-computers was to maintain multiple indices.

But current computer filesystems add another problem. You can only have one system. You can't file things by customer and vendor. One or the other has to be the top of the hierarchy. Mail clients are solving this proelm with virtual folders, but there is no (common) current support at the filesystem level for multiple topolgies.

I don't think it should be too surprising that most people don't know how to create their own topolgies. It's not something most people ever have to do. It is also why the people who do have to do it spend so much effort getting it "right".