I think you're conflating "what's released and out there" with "what's being used or distributed".
I'm saying you can test on the versions distributions are actually shipping (and the ones they're about to be using). In a lot of distributions you can rely on that staying stable for a period of time.
If your application depends on an older GTK library the solution is simple: depend on that version or ship it with your application. This is pretty unusual in the Linux world but old hat for Windows developers where you can only really depend on Win32; and for anything else your installer makes sure it's present.
And finally, for the third time, I'll state that I'm not saying there aren't legitimate issues with how GTK+ is developed. There clearly are... I'm just saying that some of the things Morten wrote show issues in their own development process as much as anything else.
I'm saying you can test on the versions distributions are actually shipping (and the ones they're about to be using). In a lot of distributions you can rely on that staying stable for a period of time.
If your application depends on an older GTK library the solution is simple: depend on that version or ship it with your application. This is pretty unusual in the Linux world but old hat for Windows developers where you can only really depend on Win32; and for anything else your installer makes sure it's present.
And finally, for the third time, I'll state that I'm not saying there aren't legitimate issues with how GTK+ is developed. There clearly are... I'm just saying that some of the things Morten wrote show issues in their own development process as much as anything else.