VSCode isn't really an IDE as much as a text editor and competitor to Sublime, Atom, etc. You can build in some languages with it, but it's not a competitor to a full-featured development environment like Intellij's IDEA or Visual Studio and not anywhere near a mobile development-oriented IDE.

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.

Visual Studio Code versus Visual Studio for Mac can be seen as something like Sublime Text versus XCode. The confusing names aside, they both target slightly different niches.