I didn't make such claim, and there's no need to comeback with such force. A file is a good abstraction of what a "casual" user works with. E-mails, documents, images, videos. These are great applications for files. Also, while some people hate UNIX's "everything is a file" approach with a passion, it's a great way to allow people to explore what's behind the wallpaper they see every day.

You know what, these big databases and object stores are living on bog standard but scalable filesystems most of the time. Ceph, ZFS, Lustre, etc., and sharded/stored as files. There are some very high performance and bespoke systems out there [0], yet they also provide POSIX compliant filesystem views outside, not because they are sacred, but because it works.

Filesystems provide great utilities for making abstractions other than files, by using files as universal containers you can play with. Again, while they are not sacred, they are an important building block, and they're here to stay. Creating a custom storage backend, throwing away all filesystem stuff is a fool's errand, since filesystems handle much more than providing a tree and some attributes on that file/folder hierarchy. Since they are the first level on top of physical storage devices, they also take care of the device underneath them (e.g. TRIM, FFFS (Flash Friendly File System), etc.).

It's a great irony that E-Mails are already stored as human readable databases on disks.

[0]: https://docs.weka.io/4.3/weka-system-overview/filesystems