What this person said is what I had heard as well...
"I've heard from industry insiders that "Firefly" was unofficially cancelled before the first episode ever made it to air because there was a new executive on board who wanted to have more time slots for "her shows", to mark her territory. Not only were the episodes purposefully aired out of order, the original pilot was re-shot in a slapstick comedy version to make it "more palatable" to the imagined audience.. which of course wasn't actually intended to work. tl;dr: According to people who would know, everything that could have been done to prevent the numbers from coming in, without being obvious about it, was done, because the show was intended to fail."