Another Good Show Down The Drain

Kings: too good to last. NBC is going to burn off the rest of the episodes in June. I still don't understand major-network TV economics. Why go to all the expense of producing a show if you're not going to try to promote it to the most likely audience (in the case of Kings, the show would most likely appeal to fans of Deadwood and other intricate cable dramas, but the promos made it look like Dawson's Creek With Butterflies)? Why not distinguish between quality tv and shitty sitcoms? Why not push the quality tv off to the expanded cable networks owned by the same company if the networks can't afford to take risks?