In an effort to be more involved in the Swift community, I have been trying to be more attentive to the Swift mailing lists, and while reading through the archives of the mailing lists I found this.
A conversation about garbage collection in Swift.
If you have an understanding of Swift’s stated goals, Objective-C’s past, or the history of client side programming, its pretty clear why garbage collection is not a great idea, however this thread went into a lot more technical detail than I had ever gone into myself, and the entire thread just gave me a much better understanding for why its against Swift’s best interests to adopt garbage collection. I highly encourage you to take the time to read it.
When reading the thread I would recommend paying special attention to answer(s) of Joe Groff, Chris Lattner, David Waite, Paul Cantrelli, Taras Zakharko and Jean-Denis Muys, their answers were particularly detailed and interesting.