Though "Idol" remains hugely popular, the show lost a quarter of its audience last season, hurt by the surging popularity of rivals such as NBC's "The Voice" and the never-ending churn of celebrity judges. Plus, the show has gotten as stale as day-old bread, which is why News Corp. chief operating officer Chase Carey recently told investors that the producers need to make the show "fresh."

"I don't think it will have the ratings free fall that it did last year, but I don't think it will return to previous levels of viewership," Shari-Anne Brill, the CEO of Shari Anne Brill Media, said in an interview. "There are so many talent competitions on the air that in the end they cannibalize each other to an extent."

Indeed, season 12 of "American Idol" brings new faces to the judge's table, including divas those of Mariah Carey and Nicki Minaj, who reportedly had sharp words for each other during the show's auditions in Charlotte, N.C. Whether that bad blood has been ginned up to boost ratings is hard to say. 

Country superstar Keith Urban is also on the judge's panel, along with Randy Jackson, the sole link to the original "Idol" lineup. The show is probably still profitable, but its expenses have to be huge. News Corp. has stuck by "The Simpsons" for decades, even as the program's popularity has eroded. Idol, though, won't be given as much slack, because of the changing economics of  television.

Comcast's (CMCSA) NBC has the highest rates, on "Sunday Night Football," where commercial time averaged $545,142, up from $512,367 last season. Media companies are spending billions on sports broadcasting rights, which have increased exponentially in value.  Some critics have argued that all consumers, even those who aren't fans, are paying the price for the industry's spendthrift ways.

The news, however, wasn't all bad for News Corp. in the Ad Age survey. Commercial prices for Zooey Deschanel's "New Girl" sitcom more than doubled to $320,940. Prices for "The Simpsons" and "Family Guy" also rose. Bart Simpson and friends commanded an average of $286,131, edging out the Griffins, who commanded $276,690 for a 30-second spot.

Fox, though, has seen double-digit declines so far this season among adults 18 to 49 -- the demographic targeted by advertisers -- as have CBS (CBS) and Walt Disney's (DIS) ABC. NBC has bucked the trend, thanks to the popularity of "The Voice." The Peacock Network also is seeing its audience become younger, which is more desirable for advertisers, while its rivals' viewership is aging, according to Adweek.

Jonathan Berr is long CBS. Follow him on Twitter@jdberr.