The other interesting part is that it's a very niche product in itself. If you go off the theory that most contributors are trying to solve a problem for themselves, then people who need an FS driver are

a) rare

b) likely to be making a commercial product, in which case the main competitor to WinFSP isn't Dokan(y), but CBFS.

The author of Expandrive could probably add more to this - his product is based off CBFS.