NEW YORK (CNN/Money) - No matter who wins this week's "American Idol" competition, the talent competition reality show has made a winner of the Fox network.

The network, lifted by "American Idol," could end up winning the May sweeps period among viewers ages 18 to 49 years old, the key demographic for advertisers, just as "American Idol" and another reality show -- "Joe Millionaire" -- let it win the February sweeps. Since ad rates are set based on sweeps periods -- one of which ends Wednesday as the winner of "American Idol" is revealed -- Fox is seeing ad sales up as much as 16 percent, according to some estimates.

Fox is the certain winner whether Clay or Ruben is declared winner on Wednesday's "American Idol."

But despite the ratings success for Fox's shows, as well as other networks' reality hits such as CBS's "Survivor" and ABC's "Bachelor," only one new reality show is set to appear on the fall television schedules released by the four major networks earlier this month. And that show -- "American Juniors," a child version of "American Idol" set to debut June 3 -- will hold the spot on the schedule for "American Idol" until its January return.

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Several other reality shows will debut this summer, including "Cupid" on CBS, which has "American Idol" judge Simon Cowell serving as executive producer. But the fall schedule, which has larger viewership, ad revenue and development dollars at stake, is surprisingly light on the reality genre.

That doesn't mean that the reality show phenomena has played itself out. Many new reality shows are poised to step in as more traditional dramas and situation comedies are canceled this fall.

One major ad buyer said he's not surprised or disappointed there aren't more reality shows on the fall schedule at this point.

"American Idol" judge Simon Cowell will be executive producer for "Cupid," a new reality show for CBS this summer.

"I'm very impressed they stuck to scripted dramas and sitcoms," said Andrew Donchin, national broadcast for media buying firm Carat USA. "There was the thought there would be too much reality on in the new season. They took a very conservative approach, and right now I think it's the right amount. The concern I have is what happens when the other shows start getting canceled."

Media analyst David Miller of Sanders, Morris, Harris said that, despite the ratings and profit success of the reality shows, he's not surprised the networks aren't flooding the fall schedule with more reality fare. There's more long-term upside to a hit drama or sitcom, said Miller, who added that a successful traditional show can last longer and produce more additional revenue than a reality show.

"Reality TV doesn't have any syndication value -- it doesn't repeat well," said Miller. "Are you going to watch 'American Idol' again once you know that Clay or Ruben won?"

Then there's the fact that not every reality show is a success. For every "American Idol," even Fox, the king of reality, has "30 Seconds to Fame," another talent competition that finished 139th in ratings and was gone after five episodes.

ABC's "Are You Hot" was one of several reality shows to fail during the 2002-03 season.

In fact, this past season was known for the reality bombs as much as the reality hits, with each network having at least one reality show it would rather forget, such as ABC's "Are You Hot," NBC's "Meet My Folks" or CBS's "Amazing Race 3," none of which could break into the top 80 shows or last as many as 10 episodes.

"There was too much saturation, too much reality product," said Miller. "If 'Are You Hot' had come around as the only reality show, it probably would have done fine," said Miller. "It's tough to break through the clutter even with reality shows."