I can't speak for the logic, but Serenity is a great movie, and the "Firefly" series as a whole was even better still... Shame that it got cancelled before it had a full chance to get off the ground.
Going back to the movie addage topic though, I've seen more and more non-Starz movies popping up, so I wonder if they did sign some new deals. One of the movies I watched the other night was "Cleaner" with Samuel L. Jackson and Ed Harris, and it was a Non-Starz movie (don't recall the studio). It was actually a pretty good movie, even though I had never heard of it... One of those obscure more recent releases I guess. What particularly impressed me though was the encode. It was encoded as SD, but the picture was very impressive for SD, and even better than many DVDs. Netflix encodes have always been better than the Starz, but they must be pushing the envelope with compression from higher res. sources.