It looks to me that Xamarin would like sunset Xamarin Studio. This was easy on Windows with Visual Studio, but on macOS I think they are waiting for the VS Code (or whatever it ends up being) to be mature enough.
In addition, VSCode is open source, so to some degree its direction depends on what the community wants to happen with it.
That being said, re-branding Xamarin Studio (which in my experience, has been buggy as all get-out) as Visual Studio Mac without many significant new features seems more of a PR move than anything else. It'd be awesome if they'd put more money/manpower towards fixing it.