Is vanilla Kubernetes easy for new developers? No, but there is an entire ecosystem offering tools and platforms to make development using containers a seamless as possible. Microsoft saw this, so they really had no choice but to adopt the container terminology and partner with Docker to try to stay relevant.
My guess is without containers, Microsoft would have never even built WSL. If you want smooth developer experience with containers then that is what solutions like GitLab offer. Even Microsoft's GitLab is essentially built around running various actions inside containers.
I personally welcome the change. I can spin up a local Kubernetes cluster and test an entire cluster of applications locally if I want, or integrate it into Skaffold or whatever else and test live in the cloud. It really is a lot better than what we had before. I think the solutions though really come down to documentation and resources to help train new employees and acclimate them.
Also:
> Consider also that Docker relies on Linux kernel-specific features to implement containers, so users of macOS, Windows, FreeBSD, and other operating systems still need a virtualization layer.
First, FreeBSD has its own native form of containers and Windows has its own native implementation. Docker != containers.
I really don't see how Docker (or containers as we mostly know them) relying on kernel-features from an open source operating system in order to run Linux OS images as something to even complain about, and there is nothing preventing Mac from implementing their own form of containers.