Why anyone would want to use Apple code, period?
Making a "free" open source code "closed" so your users aren't free to do things like change it, pass it on, or use it for themselves in another way, isn't "freedom."
Lots of people are using Gnu-based code on (shock) WINDOWS, including new GUI's that bypass the Windows 8 interface, entirely, making it more like whatever flavor of OS you like (and I can see that happening because a lot of software written for Windows just won't work under any other OS including in WINE and people perceive they need some particular thing instead of an alternative, or it's too costly to switch, especially in cases of company-specific programs written a few years back that's irreplaceable or would take too long to port or update.)