I first saw this via Glyn Moody’s tweet. I hadn’t realized that Songbird was a company, presumably for profit, rather than just a project. The reasoning about being spread too thin, then, makes more sense.
I have tried Songbird repeatedly since it first launched. It always feels almost finished but never ready for regular use. My biggest complaint is that it has never successfully and consistently handled podcasts, either discovered via browsing or entered manually. Maybe their current push towards a new milestone version will fix that. I remain skeptical.
As the announcement notes, they will still make a Linux build available and a few resources to back it but won’t be testing the build or adding new features. Implied in that concessions is that perhaps in the future, they may be better able to bring the Linux build back into the fold.