Half the world has an IQ below 100. Computers need to help and serve them, too.

The threshold for comfortably managing hierarchical file systems is around 100 IQ. For doing it well is several points higher.

And eliminating access to the file system makes app developers get creative about inventing new ways to make things easier for users. A lot of data is relational and not compatible with the file metaphor. Some data is a net of objects (not as much as OO language designers seem to think). New ways to interact with those are valuable.

Of course, the flexibility of the file system has a lot of advantages. It invites a powerful and uniform set of tools that can make it even more flexible. That's why it continues to be useful. Nevertheless, other ideas, like relational data as a universal system service, are setting in to give it competition.