^ The execs at FOX greenlit Firefly because they wanted another Joss Whedon show. They didn't understand the premise of the series when Joss pitched it to them, but greenlit it anyway. They were expecting his name alone to get them ratings, and when that didn't happen, they used the ratings as an excuse to get rid of their 'greed-fueled misstep'.
There's no guarantee that the series would've succeeded and been longer-lasting if it had aired on a network other than FOX, but the execs who were there at the time had no business greenlighting the series in the first place.
Joss was under contract to produce new series for Fox and all Fox did was ot buy one of his series. He was given plenty of money to make the series and it got cancelled because it failed to produce the ratings needed to survive. IT should be noted that John Doe the show on right after Firefly had double Firefly's ratings and was also cancelled.
The greatest science fiction series of all time is
Doctor Who! And I'll take you all on, one-by-one
or all in a bunch to back it up!"
--- Harlan Ellison, from his introduction
to the PINNACLE series of Doctor Who books