Contestants? It's TV talent judges basking in fame, cash LOS ANGELES (Reuters) - Time was when TV talent shows set out to turn wannabes into stars. These days? Not so much. It's the celebrity judges who are raking in the cash and using TV contests not only as a way to re-launch a fading career, but to further boost a thriving one. For music stars in an era of weak record sales, the trend spells victory for their bank account, but for fans and the music industry always hungering for a new star, it's a loss. And for TV networks, the once cheap-to-produce shows are ever more expensive, yet they don't always pay off in bigger audiences. As recent winners of "The Voice" and "American Idol" fade into obscurity, pop princess Britney Spears and ex-Disney Channel teen star Demi Lovato have signed up to judge "The X Factor," while controversial radio DJ Howard Stern is the biggest star on the new season of "America's Got Talent." Spears and Stern are among the most highly-paid TV judges, each earning a reported $15-$20 million annual salary - a bigger figure than many A-list Hollywood actors command for a movie. The whole playing field has shifted from when 'American Idol' started (2002) and the judges were people whose biggest hits were behind them. Now it is seen as a really viable option for current artists," said Melinda Newman, a music blogger for entertainment website Hitfix.com. Spears and Stern join a roster of celebrity TV judges that includes Christina Aguilera, Steven Tyler, Sharon Osbourne, Cee Lo Green and Blake Shelton who have seen their fame, record sales and endorsement deals skyrocket since they began sitting in front of the stage rather than on it. Kelly Clarkson, the first "American Idol" champion and now a Grammy-winning singer with worldwide celebrity, joins the judge club next week on "Duets," which pairs would-be singers with established stars. Lyndsey Parker, managing editor of Yahoo! Music, said a lot of people were surprised at Clarkson's decision, but "no-one is looking at that as a step back." With the focus on the judges, what happens to the wannabe pop stars these shows were supposed to discover and promote? "The unfortunate thing is that as there becomes more emphasis on hiring famous names, it goes off the contestants," Parker said. Back in 2002, record producer Simon Fuller - the man behind Britain's "Spice Girls" - created "American Idol" as a way to discover and sign new singers to his 19 Entertainment group. Few people had ever heard of judge Simon Cowell, an acerbic British record producer. Host Ryan Seacrest was an ambitious Los Angeles radio DJ, Randy Jackson was a backroom record producer and Paula Abdul was an almost forgotten 1980s pop star. Fuller's format worked for several years, turning Clarkson, Carrie Underwood, Clay Aiken, Jennifer Hudson, Chris Daughtry and Adam Lambert into bonafide recording artists bringing in millions of dollars for record companies. But by 2011, given the success of the show as the most-watched program on U.S. airwaves averaging well over 20 million viewers a week, the dynamic of making a celebrity had shifted. That year, "Idol" champion Scotty McCreery saw his debut album sell more than one million copies, but his success was dwarfed by that of incoming judges Jennifer Lopez and Aerosmith frontman Steven Tyler. Lopez, who had been dropped by her record company before joining "American Idol," scored her biggest single ever with "On the Floor," launched a fashion line, got her own Latin music talent show, multiple endorsement deals and a world tour. This week Lopez topped the annual Forbes list of the world's 100 most powerful celebrities. Tyler, 64, has won new fans, written a book and pulled Aerosmith back from the verge of an acrimonious break-up and into the recording studio for the band's first album of original material since 2001. Tyler probably opened the door in a huge way because he is a rock legend. I think a lot of people were surprised that someone of his stature would do it," said Parker. Also in 2011 came "The Voice," which has proven to be one of the few ratings winners for NBC. Yet, last year's champion Javier Colon and runner-up Dia Frampton didn't even crack the Billboard top 100 with their debut albums. Moreover, while the show has been an NBC bright spot, it failed to challenge "American Idol" for overall viewers this year as strongly as some industry experts had predicted. About 15 million viewers tuned in for "The Voice" on average this year, compared to more than 19 million for "Idol." The stars of "The Voice," however, fared better. Judges Aguilera and Maroon 5 frontman Adam Levine had one of the world's biggest selling singles of 2011 with "Moves Like Jagger" which they first performed on the show. Country artist Shelton has seen his mainstream star soar since he joined "The Voice." Jermaine Paul, last week's winner of the second season of "The Voice" has yet to produce an album. His cover version of "I Believe I Can Fly" fared well on iTunes the day after his win, but it was a blip compared to Maroon 5's "Payphone" single with rapper Wiz Khalifa, which debuted on "The Voice" in April. Now entering the fray are Spears and Stern, who were hired by Cowell in a bid to produce bigger ratings for their respective shows: "X Factor" which returns in Fall 2012 and "America's Got Talent" which debuted this week. Stern, the self-described "King of All Media" whose satellite radio show on SiriusXM is reported to earn him some $80 million a year, insists his reason for doing "America's Got Talent" is simply that he is a big fan of talent shows. I didn't need the money. I didn't need more fame. I certainly feel famous enough. I certainly feel I am comfortable in my life and I am happy about that. I just love the show. And I thought, 'wow, how much fun to do it,'" he told reporters in a news conference last week. Yet for all the fanfare around his hiring, Stern's first outing this week on "America's Got Talent" was watched by about five million fewer people than last year's season kickoff. Then there is Spears. After almost 15 years as a global pop icon, the former Disney star now 30 and a mother of two kids, may have a different motive than Stern for joining "X Factor." That is a steady paycheck without having to go on the road. That is how she makes her money now, not by record sales, but by touring and endorsement deals," said Parker. But will she bring more viewers? That is, after all, what producer Cowell and broadcast network Fox hope she will do. And if so, will those viewers create the world's next big thing in music like "American Idol" once did? Last season's "X Factor" winner, Melanie Amaro, had little impact on the U.S. music scene with her first single and five months on, she is still working on her debut album. Times have changed, and Andy Dehnart, editor of RealityBlurred.com, expressed concern for Spears. "I think 'X Factor' is a gigantic ego trip for Simon Cowell and I worry that Britney is another piece of that," he said. That's not to say TV talent shows don't occasionally still find stars who eclipse their mentors, such as British boy band One Direction. But "now it seems like all the shows are trying to one up each other by stocking their judging panel with people who are already famous, and that does make it harder for the contestants to stand out," said Parker. Additional reporting by Christine Kearney; Editing by Bob Tourtellotte and Patricia Reaney