The problem with this view is that the alternative to serverless is not spending money on bare metal servers, but renting actual or virtual servers on a month to month basis.
(Cheaper that is if you don't value your employees time, which most large companies don't.)
Once you have enough load to justify going “unserverless” the prices drop to approximately 1/4 that of Cloud Functions for the same burst performance, and that’s before playing billing games like long-term commitments or using preemptible instances.
What’s truly scalable about “serverless compute” versus VMs is the line item on your bill. Sure, “they manage the auto-scaling” but for the per-unit price you rapidly hit a point where you might as well set up a Kubernetes load balancer and eat the setup costs. The pricing model only works out in your favor if you _don’t_ have load.
It would not surprise me to learn that the same is true of AWS prices.
* monitor lots of things like filesystem usage and CPU usage
* build new machine images (as well as possibly new container images!) to keep up with security updates
* tune autoscaling at multiple levels based on whichever server-based systems you're using
* maintain a secure way for production support folks to log into servers to see what is going wrong or perform emergency fixes
* build additional failover automation as well as what you'd already need for serverless