maybe not 25 years ago... but it was common in the early '00s. This is not new tech. I participated in a project to do this with FreeBSD and nfs, I think around '03 or so. It was a smallish cluster (under 100 nodes) built to handle a simple Freebsd Apache Mysql PHP stack for a growing realestate ASP. Even then, it was not a new thing; there was plenty of documentation from other folks doing it.

I mean, it didn't go as smoothly as pxe booting does today; we ended up needing to reflash all our network cards to make it work, something I have not had to do in the last 5 years.