Now, if Apple actually released the code of its Windows port of iTunes, will Apple actually care about it enough to accept the contributions from the community and make the community feel welcome? Will iTunes on Windows drastically improve as the time goes on? Will developers on other platforms accept it and use it for their products? How well does it behave when compared to other programming languages? There are too many unknowns.
Although I'd love to see that future, I don't think that this will happen. In theory, releasing the code of something is all that is needed to do to make something actually useful. In reality, things are not that simple.
Right now the issue is library support - swiftc can already just spit out LLVM IR: https://github.com/kripken/emscripten/issues/2427
The stdlib would be included in the open source release.
Linux boxes would fulfill "non-Apple product" though. Unixy programming languages like Swift and Python have always been weird on Windows.
Even then, building some of the fancier libraries (with native code) by hand is bit involved.
In fact, Anaconda works very well on Windows, as long as you don't require extreme latest versions of modules.