Kubernetes isn't the source of complexity - it is the problem domain of building and operating distributed systems that are fundamentally and essentially complex.
Compare the complexity of Kubernetes to Openstack - the next most similar project in the same problem space, and you will find Kubernetes is actually pretty simple.
OpenStack and Kubernetes serve different purposes. Despite the article, Kubernetes at its core really is a container orchestrator. OpenStack is a collection of software you'd use for running a mini-AWS on bare metal infrastructure.
Compare the complexity of Kubernetes to Openstack - the next most similar project in the same problem space, and you will find Kubernetes is actually pretty simple.