> If you have a system that's actually big or complex enough to warrant using Kubernetes (...)

I think there's a degree of confusion over your understanding of what Kubernetes is.

Kubernetes is a platform to run containerized applications. Originally it started as a way to simplify the work of putting together clusters of COTS hardware, but since then its popularity drove it to become the platform instead of an abstraction over other platforms.

What this means is that Kubernetes is now a standard way to deploy cloud applications, regardless of complexity or scale. Kubernetes is used to deploy apps to raspberry pis, one-box systems running under your desk, your own workstation, one or more VMs running on random cloud providers, and AWS. That's it.