Perhaps one would appreciate the series more if one was familiar with the mythological history that invigorates its story. I enjoyed the series tremendously for this reason, and because it presented a vital alternative to the usual fare. A different story with all the same tropes of the genre would have been unexciting. Also, the series tries to cross two genres (fantasy and cop dramas) that probably don't cross well in the American cultural consciousness. The people that enjoy high fantasy and ancient mythology (to put these two together) likely aren't the same people who enjoy gritty cop dramas. That is, the audience is not sufficiently large to justify the show's continued existence.
Likewise, though for different reasons, I attribute the demise of Farscape. It was innovative in ways that a large audience did not sufficiently appreciate, though I would have thought that its audience was sufficiently large for continued production. Again, the danger of breaking conformance to cultural consciousness.
