> My contention is that they could have instead replaced VolFs with a native WSL1 file system that uses a disk partition or VHD as its backend storage, thus eliminating the Windows I/O stack in the same way. They could then have implemented proper Linux file system semantics without any baggage.

But that would require them to implement a new file system from scratch wouldn't it? VolFs in WSL1 relied on NTFS to do the heavy lifting.

Far easier to just let the Linux kernel handle it.