Yeah if you were really trying to make things fast you'd have the compute and NFS server in the same rack connected this way. But you aren't going to get this from any cloud providers.

For read-only data (the original model is about serving file weights) you can also use iscsi. This is how packages/binaries are served to nearly all borg hosts at Google (most Borg hosts don't have any local disk whatsoever, when they need to run a given binary they mount the software image using iscsi and then I believe mlock nearly all of the elf sections).