I guess I have to earn your trust too. I was actually intimately familiar with Netapp filers at the time, since that is what we used to drive the NFS mounts for the desktops at the first place I mentioned. They were not as immune as you think and were not suitable.

Also, we were a startup, and a Netapp filer was way outside the realm of possibility.

Also, that would be a great solution if you have one datacenter, but as soon as you have more than one, you still have to solve the problem of syncing between the filers.

Also, you generally don't want all of your app servers to update to new code instantly all the same time, in case there is a bug. You want to slow roll the deploy.

Also, you couldn't get a filer in AWS, once we moved there.

And before we moved to AWS the rack was too full for a filer, I would have had to get a whole extra rack.