Well, on reading the little thing on that page with it, they basically say one of the main reasons the show flopped is because the theme song was all western-y, which is just complete bullshit. Like Light said, the series was supposed to be a Space Western, and giving it some synthie, 80s soundtrack would have been the stupidest thing they could have done.
No, the main reason, IMO that Firefly was cancelled was because people didnt know when the goddamn show would be on, with FOX constantly changing the timeslots and playing the NEW episodes in the wrong freakin order.
Blame FOX, not the series.