The migration tools existed immediately when Apple updated Swift, because it came with an update to Xcode as well, so I'm not sure how you moved it by hand before the tools existed, especially considering Xcode was in pre-release with those features implemented before it RTM'd.
There were C++ IDEs before Turbo C++. Turbo C++ was a worse IDE than Emacs, Brief, or Epsilon back then. The only difference is that it was easier for pure novices to learn to use (which is important when learning to program - you don't want the tooling to be a distraction).
IDEs back then were not the same as IDEs today. Language Facilities in C++ in 1988 were about 70% less than what is there today. Between 89 and 90, C++ gained multiple inheritance, abstract classes, static member functions, const member functions, and protected members, templates, exceptions, namespaces, new casts, a boolean type, and other facilities.
C++ in 1988 compared to C++ in 1992 is like comparing Turbo Pascal with Objects to Delphi 4. Things like the Standard C++ Library make working with the language without decent tooling a huge PITA, never mind the Libraries and Frameworks we may use on a system-by-system basis for things like GUI programming.
I am not really sure WTF you're trying to point out by rhetorically stating that Visual Studio is a Windows-only development product. It's the standard on Windows and it's the IDE that most commercial toolsets are built on. It also does not require a third party runtime with a sketchy desktop security history to be installed (.NET is pre-installed on Windows machines).
Developing Visual Studio extensions is not hard. Apple should work on making Xcode equally extensible, IMO.
There are still older-style IDEs available for Windows (UltraEdit Studio (also on Mac and Linux), SlickEdit (also on Mac and Linux), and CodeWright (out of development, but still being sold for Windows) - Epsilon is still developed and sold.
However, Swift support is obviously weak.
I'm not the one pushing Swift as the best thing since the invention of fire. Apple is. They should develop better tooling for it.