I'm a bit out of my element so I apologize if I'm missing something.
Microsoft implemented cgroups and namespace analogues in Windows Server 2016 to allow it to run "real" Docker containers without the need for virtual machines. The limitation is that the real Windows containers can only run Windows based applications because the underlying architecture is still Windows. Something similar would happen with macOS. The underlying architecture of macOS would remain macOS regardless of whether it could run real containers or not.