The unauthenticated limit doesn't bother me as much, though I was little upset when I first saw it. Many business doesn't bother setting up their own registry, even though they should, nor do they care to pay for the service. I suspect that many doesn't even know that Docker can be used without Docker Hub. These are the freeloaders Docker will be targetting. I've never worked for company that was serious about Docker/Kubernetes and didn't run their own registry.
One major issue for Docker is that they've always ran a publicly available registry, which is the default and just works. So people have just assumed that this was how Docker works and they've never bothered setting up accounts for developers nor production systems.
Like, I get it, but it adds considerable work and headaches to thousands (millions?) of people.
Not Docker, but I worked on a project that used certain Python libraries, where the author would yank the older versions of the library everything they felt like rewriting everything, this happened multiple times. After that happened the second time we just started running our own Python package registry. That way we where in control of upgrades.
Nexus is very easy to set up.
You should also run your own apt/yum, npm, pypi, maven, whatever else you use, for the same reasons. At a certain scale it's just prudent engineering.
Own your dependency chain.