This is not a valid comparison. You're comparing bare metal virtual machines wherein you are responsible for all of the software running on the VM, with a bundled set of tarballs containing binaries you probably cannot reproduce.

Many, many vendors provide docker images but no Dockerfile. And even if you had the Dockerfile you might not have access to the environment in which it needs to be run.

Docker is successful in part because it punts library versioning and security patches and distro maintenance to a third party. Not only do you not have to worry about these things (but you should!) now you might not be able to even do anything if you wanted to.

> Docker is successful in part because it punts library versioning and security patches and distro maintenance to a third party. Not only do you not have to worry about these things (but you should!) now you might not be able to even do anything if you wanted to.

This is a very restricted view.

Besides this article is about building your own images, not using existing ones.