Flyfly: Why Did This Get Cancelled?

So I started watching Firefly on DVD. This was a TV series which aired during the 2002-2003 season, but was cancelled after only airing 11 episodes. The series is excellent. I'm rather disappointed that the FOX network cancelled the show.

But the movie is coming out Sept. 30. I'll most likely wind up waiting for it to come out on DVD (and will buy the DVD) as watching movies in the movie theaters just isn't fun anymore.