This is depressing.
Even more depressing is that macOS still doesn't seem to have native containers. (Correct me if I'm wrong - perhaps the sandboxing system can be used as a container system including virtual network interfaces attached to process groups?)
Docker images depend on Linux which means "Docker" on macOS runs in a Linux VM. Presumably docker for Windows could use WSL.
WSL2 is also a VM. Docker is in truth Linux-only software, and "Docker" on any other platform is a polished interface for spinning up a Linux VM and running the real version of Docker there.
I don't think this is such a bad thing. What non-Linux Docker really provides is a nice UI.
On my Mac, I switched from doing a lot of development in VMWare Fusion to using docker-machine (set up to still use VMWare under the hood). With docker-machine especially, it's quite obvious that I'm still just using a VM, but it all feels a lot more seamless than when I was running a bunch of commands to start up VMWare, SSH in, and sync my local files.
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† I can't use Docker Desktop because I insist on running an old version of OS X.
Docker containers are an amalgamation of features, tweaks, and functions which combine together into one experience. There is no kernel concept of a container. There are cgroups, namespaces, capabilities, chroots, CoW Overlay VFS, bind mounts, firewalls, virtual networking... And a whole lot of custom crap Docker provides. You have to have a lot of custom glue to make it all work. You need "a Docker".
Every attempt to make a replacement for Docker falls short because of how many things it has to touch to make things easy to use. To replace it all (since it's not an OS primitive) requires product development, which is expensive and complicated, and probably not vendor-compatible with Docker anyway. So you might as well just have people run Docker.
Containers fundamentally change the concepts used to maintain and operate applications in OSes. I think eventually they will become core features, but it's going to take a while. Someone's going to need to start sending in some pretty big patch sets one piece at a time, such as kernel drivers for all the various features. OCI also needs a lot more help before we can run a container everywhere, and it will undoubtedly involve some virtualization layers we don't yet use as part of containers, which will add more complexity.
Docker containers are reliant on Linux cgroups, so even if macOS had its own native containers, it would need to add a Linux cgroups compatibility layer on top of it for Docker to work natively.
I always found that to be weird as well, since AFAIK Darwin does have jails, but it's only used on iOS for some reason (unless I've misunderstood what "jailbreaking" means).
Jailbreaking in the sense it is used for breaking out of the Apple defined jail/walled garden.
Darwin does not have jails as FreeBSD does. And the software they have for limiting what an application can do is not in any way similar to what a jail is.