Same thing happened with OS/2 when they offered the ability to run Windows software -- practically no native software outside of IBM's own (and even then, in some cases, depending on division!) resulted in a user-base with a lot of Windows software. The logical upgrade path end up being to go to Windows, especially when you find updates of software you already own don't work quite right on your "guest API" implementation.
Quite, that really happened, it wasn't because the few months in late 1994, early 1995, when OS/2 began to seriously take off, were not enough time for commercial software developers to build a large body native software.
The same thing, of course, happened to Mac OS X. They rather stupidly included all the Mac OS 9 APIs in a compatibility box called "Classic". As a result, nobody ever developed any native Mac OS X software, and the platform just died. I wonder where it is today?
Seriously, this computer urban myth has to stop. No operating system has ever faced a lack of commercial software because it ran an opposing operating system's software well.
- OS/2 was around for a while, but it was only actually popular for a very brief period, not enough time for developers to catch up before Microsoft threatened IBM over Windows 95 and IBM stopped marketing it.
- Mac OS X and Windows NT (2000, XP, and Vista are versions of Windows NT) both supported the APIs of the operating system they replaced, and both Cocoa/Carbon, and Win32, took off as soon as the developers understood the OS was going to be around and supported for a while, and that the cleanest looking apps would be the native ones.
- GNU/Linux has had Wine for a while, including versions that can be cleanly linked in to programs statically so the end user doesn't even know they're running a Win32 application. Despite this, there's arguably as much or more software for GNU/Linux today (despite its lack of marketshare) than there is for Windows.
What actually matters to developers are:
- Does my app look good on the target platform(s)?
- What target platforms will still be around three or four years from now?
- Will I be able to distribute my software and get back what I'm expecting to get back?
Let's suppose the highly unlikely "Red box" scenario comes to fruition:
Realistically, anything (with the possible exception of games) currently being ported to Mac will continue to be. Anything currently platform specific will stay platform specific. And the new apps will be as evenly divided between the two camps as they always were. The difference will be you'll finally be able to run the platform specific camp's software.