I've been looking at the various promotional efforts for Serenity as a experiment by Universal to see what the marketing people can do if they're turned loose. They had a good movie to experiment with--built in core audience to spread word of mouth, and a favorable reaction from critics. But it didn't get a huge opening, and it didn't get lots of people coming from word of mouth recommendations. For executives afraid that word of mouth driven hits are gone forever this may be the proof. Box office revenue is already shrinking, so at some point it won't make sense to do a theatrical release instead of going straight to DVD.
There's already plenty of direct-to-video movies, but they're bad. This is the fate of movies too good or expensive to be just thrown away, but not worth trying to promote for the theatre. Even ones originally intended for DTV are done poorly, since no one seems to feel it justifies their best work. But if DTV becomes the main profit sector for the studios that'll have to change.
So if Universal is going to ahead to the future of the business, it'll have to do some experiments to figure out how to market high-quality DTV shows. Serenity seems ideally positioned to be a test case. They're measuring the appetite for DVDs (as opposed to theatre showings) with a December release. If that's a bigger hit than the movie was on the big screen, it'll look like a good opportunity for a DTV sequel. After Firefly was cancelled, some fans were pushing for a subscription DTV follow-on. That could be a good model for Serenity, getting some revenue up front to justify the investment in making new episodes.
I'd also like to see DTV for the freedom it gives artists. Right now movies and TV have very rigid constraints on the stories they can hold. TV has hard time limits and requires a climax or cliffhanger before each commercial break. Movies are more flexible but still force the story into continuous high gear (I think the non-book scenes in the LotR trilogy were mostly there to maintain the rising tension). With a DTV mini-series Joss could do stories at the Firefly pace, and let them include all the little touches that make us fans.