I only recently got into Firefly, and it's definitely one of those shows that you either "get" or you...don't. I feel that if you give it a chance, you'll "get" it after a couple of episodes. If you don't, or only watch one episode (depending on the one you watch), you might not get it.
That's the problem. Airing out of order, moving timeslots, all that stuff...it doesn't matter to a show like NCIS or CSI, or most comedies...because you "get" it right away. The premise hits you from the first 5 minutes. Firefly doesn't, and that's why it needed consistency.
When the show was on I remember I caught one episode, the original pilot "Train Job." I thought it was decent, but nothing great (and I still do; it's my least favorite episode), and then I never saw the show again. Never saw a promo, and if it was indeed on Friday night, then their key demographic - which I was firmly in - was out drinking. Put it on a Tuesday or Wednesday, and I would have given it another shot. Just saying.
I never got the Friday graveyard. The right show COULD work on that night. It's just your audience. Who's home? My parents. Older folks in their 40s - 50s+. Little kids. So you put on your "family friendly" comedies. I could see Meet the Browns succeeding on a Friday. That's the only really family friendly sitcom that I can think of that still exists. Full House and Family Matters worked on Fridays for YEARS. They just knew their audience. And then for the old folks, they watch NCIS. I dunno why, but my parents and all their friends and just about everyone over 40 I know loves that show. CSI Miami. Those shows could work too. But putting a show aimed at young people on a Friday is a killing stroke. They knew it then and they know it now.