Comment by xyzzy_plugh

You're kind of right. But at the same time they are nowhere close. The beauty of Linux containerization is that processes can be wholly ignorant that they are not in fact running as root. The containers get, what appear to them, to be the whole OS to themselves.

You don't get that in macOS. It's more of a jail than a sandbox. For example, as an app you can't, as far as I know, shell out and install homebrew and then invoke homebrew and install, say, postgres, and run it, all without affecting the user's environment. I think that's what people mean when they say macOS lacks native containers.