You're not building everything from scratch on-prem. There are excellent tools for deploying and managing infrastructure like Terraform, Ansible, Puppet that

You're not building everything from scratch on-prem. There are excellent tools for deploying and managing infrastructure like Terraform, Ansible, Puppet that funny enough are used to deploy to cloud as well. Add a self-hosted Kubernetes cluster to that and your on-prem is not that different than a cloud. As for ops people - you might not need an engineer to replace failed hard-drives, but you'll need a DevOps person to manage Cloud Formation templates and such, and they cost more.