The criticism of the file system as overly simple or archaic is often been made, ever since the 70s. However the fact is that it IS use-able as a base for ACID capable software. Numerous reality based evidence attests to that.

I remember in Rochkind's book[0] there is a quote criticising Unix being inferior to IBM's MVS because it didn't have locking. As Rochkind retorts, MVS didn't either! Not as a kernel feature, but via user space software, which is eminently do-able in Unix too.

[0] https://www.oreilly.com/library/view/advanced-unix-programmi...