Surely 'the other factor' is no factor at all as IaC can target on-prem just as easily as cloud?

Many people do inaccurately equate IaC with “cloud native” or cloud “only”.

It can certainly fit into a particular cloud platform’s offerings. But it’s by no means exclusive to the cloud.

My entire stack can be picked up and redeployed anywhere where I can run Ubuntu or Debian. My “most external” dependencies are domain name registries and an S3-API compatible object store, and even that one is technically optional, if given a few days of lead time.