Honest question: why do we need wholly separate devops/infra teams as opposed to just one expert to teach the other devs if K8s was supposed to make IaC so efficient?
The same reason frontend and backend teams exist. At a certain point it makes sense to have centralized teams focus on specific verticals than requiring everyone to learn/know about everything. As with any tools, there are right and wrong ways of using it and using the wrong tool for the job can sometimes be more painful than not using it at all.