The filesystem abstraction can only work when it's used by cooperating, well mannered consenting adults. At it's core it is just a hierarchical key-value store where the core os plays a middle manager role connecting applications looking up keys and filesystem plugins serving values and persisting them onto the kernels block device apis.
It certainly can be a convenient and productive abstraction but the model itself has very clear natural limits.
It certainly can be a convenient and productive abstraction but the model itself has very clear natural limits.