That's a very odd and factually wrong generalisation.

I don't use helm at all, and I manage a large scale platform built on Kubernetes. Everything is either declared directly in YAMLs and deployed with `kubectl apply -f <YAMLs or directory containing them>`, or rendered using Kustomize and, again, deployed using `kubectl apply -f -`.

Kustomize can be rough around the edges but it's predictable and I can easily render the YAMLs locally for troubleshooting and investigating.