Sure, at some point you have to let the abstraction leak. At the time Sun designed NFS, you could basically count on the fact that the server was some Solaris machine capable of multiple years of uptime on your LAN. Filesystems never made the transition to running over the internet because that was too unreliable and POSIX didn't really provide the right interfaces to expose that.

We're coming to the end of the road with that generation of OS design - MacOS is still Unix and thinks that it's running on a VAX. There's a reason why Macbooks don't come with a 5G modem: because programs would have to be aware of the underlying network. That's why it's inevitable that we'll move to something like IOS (or Android), because every program that uses the network has to handle not only failures but situations like being in flight mode or running on low-bandwidth mobile networks.