Seen here
People are under the mistaken impression that Fox is an entertainment company producing shows as a product for viewers who are their customers. Incorrect.
Fox is a media company, and their product is viewers, which they sell to advertisers, their actual customers. Apply this knowledge to "news" channels, etc... and you'll understand a lot.
That business model means that any actual quality entertainment is a fluke. Especially if it's something deemed such quality that a small demographic really enjoys it... that is never their goal. Understanding this, one can look for quality entertainment in books, or films and shows *after* they aired and were reviewed well, despite the system.
The interesting question is not "why does Fox screw up at something outside of their goals." The interesting question is "what method of funding and creating shows as quality entertainment might be sustainable as a business that we could flock to?" Distributed digital patronage or something? Maybe I should submit that as an Ask Slashdot.