I am not sure that is true. I ran fleets of FreeBSD machines 20 years ago and we dd'd disks to spin up new hosts, PXE booted some, local and remote (NFS) storage. Even in the 90s, machines were cattle.

The pieces are largely the same, but in a lot of ways, the tooling has _enabled_ more complexity than is necessary. Things have become specialized in incongruent ways that makes things harder. Simplicity is a constant struggle and a quality all of its own. Sometimes you have it by accident, where it then occupies the unknown known quadrant.