Sure they do but they use extremely specialized software that probably took years to apply to the platform let alone developing the software. Linux is the top in distributed computing because it filled a niche (free) and has momentum if BSD, L4, etc was created then / didn't have some sort of issue we'd all be using kernel x instead of linux
c, capabilties (or lack there of), self healing, runtime based optimizations, concurrency, locking, threading and just generally the way it's structured it's not meant to be a distributed operating system the applications developed for it show this. Have you seen how glusterfs, lustre or any other distributed FS works? They bend over backwards trying to implement a POSIX API usually with hideous hacks.
