It’s difficult to sell a show with hard sci-fi or fantasy elements. It doesn’t matter that the biggest summer movies (Spider-Man 3, Shrek the Third, Pirates of the Caribbean: At World’s End, Transformers, Harry Potter and the Order of the Phoenix) and book (Harry Potter again) are sci-fi or fantasy, or even that “Heroes” was the highest-rated new show on TV. Try pitching a purely sci-fi/fantasy show with a spaceship or an elf and see how it goes over. Put an elf on your spaceship and you might never recover. Even the SCI FI Channel seems reluctant, as they look toward a post-”Battlestar Galactica” era, to dive too deeply into Asimovian or Tolkienish waters. Non-cable networks are even more wary. And their reasoning isn’t terrible. Networks are still in the business of broadcasting, not nichecasting. You simply cannot make a hit show by attracting only viewers who also attend Comic-Con, no matter how hard it is to move down a San Diego sidewalk in late July.
You can read the entire thing here; it’s well worth a look.