This kinda makes the mistake that nearly everyone makes with regard to containers: They view the container as a black box into which complexity disappears.

A container doesn't consume complexity and emit order. The complexity is still in there; you still have to build your containers in a way that is replicable, reliable, and automatable. I'm not necessarily saying configuration management is the only way to address that complexity, but it does have to be addressed in a container-based environment.

Now, I understand that in many cases some of the complexity is now being outsourced to others who maintain the containers (in the same way we've been outsourcing package management to operating system vendors for a couple decades), and so maybe some of the complexity has been pushed outside of your organization, but you have something being deployed that is internal to your org, so you have to deal with that complexity. Container management tools just don't do things at that level.

There's always a point where what you're doing is unique to your environment, and you have to be able to manage/reproduce/upgrade it somehow.