> If i recall one of the biggest selling point of lambda (serverless) was the “infinite” scale

From zero to "infinite", so very useful for highly variable or completely unknown workloads. Especially with the container version migrating away isn't a massive undertaking, so it's still very useful as a starting point.

Thats true. I think the example from AWS is some once in a quarter data ingestion being much, much cheaper on lambda, and of course if you have your own build machines then you are limited to how often you can build without having people waiting.

But if you want low maintenance efforts, then you can get managed Kubernetes.

Sorry but managed Kubernetes is not low maintenance like Faas. I had a kubernetes upgrade fail and it was not fun to stand up a new cluster install newer versions of the ingress that could not longer be upgraded, migrate all the workloads. The k8s cluster is still very much your problem