The signs are undeniable at this point.
No 64 bit support for Visual Studio
The very first sign was when Microsoft refused to port Visual Studio (VS) to 64 bit. While VS is indeed a large codebase, MS had no qualms doing the same for Microsoft Office. The fact that they no longer want to invest too much resources into it should point to the fact Visual Studio is very much in maintenance mode now.
VS Community == VS Pro
Visual Studio was always paid software. But in 2014 MS introduced the Community Edition. The only real difference between it and the Pro (paid) version is the 'Code Lens' feature. Another sign that MS no longer sees Visual Studio as driving any meaningful revenue.
Language Service
Every Microsoft language release now comes with a Language Service feature which allows all the IDE style functionality like refactoring, code completion, etc to be tied to the version of a language. Any editor can use the Language Service API to get all the IDE features one would traditionally only get from Visual Studio.
Continued Investment in VS Code
Visual Studio Code continues to release enhancements every single month, moving at a fast pace. Compare that to Visual Studio Pro, whose development seems pretty much only about updating its integration of the various Language Services to the latest version.
Cross Platform and focus on Azure
With Microsoft's focus shifting from Windows to Azure, it is but natural that they no longer want an IDE that runs only on Windows. Thus comes in VS Code, a free, cross platform IDE that supports all modern languages.
Conclusion
Visual Studio was the very first IDE I used when growing up and learning to program. Its nostalgic to see it go. But the future looks bright in VS Code!