Ratings but that was mostly due to FOX.
They had it on a Friday night timeslot. Remember this was before the TiVO revolution. Friday night was where shows go to die, not start. Also the same timeslot where sports pre-empted over it. You go to turn into some space cowboy adventures and get football instead. FOX also aired episodes out of order screwing up all the character development.
Exactly this. It was a mess.
I tried to watch Firefox when it was first broadcast.
But out of order and pre-empted, I thought it was just "meh". Later a friend loaned me the DVDs, I binged it, and then thought it was fantastic.
Firefly is the perfect example of how to kill a good show with scheduling nonsense. Though that would happen less today with all the viewing/streaming options.