That abstraction was highly dependent on physical storage unit attached to your device of choice.
When most of storage is moved to the cloud and the books are stored in my Dropbox, private photos on my Flickr and public photos on my Instagram, it no longer matters that the underlying abstraction is using files and folders - they could switch to streams (case in point - iOS), and most users wouldn't care.
When most of storage is moved to the cloud and the books are stored in my Dropbox, private photos on my Flickr and public photos on my Instagram, it no longer matters that the underlying abstraction is using files and folders - they could switch to streams (case in point - iOS), and most users wouldn't care.