By Jennifer Armstrong
Updated April 29, 2009 at 12:00 PM EDT

Simon Cowell has publicly declared that he may walk away from American Idol when his contract expires after next season, hinting (repeatedly), “Maybe it’s time for a change.” That should have executives quaking in their loafers, as Cowell is the face of a show that’s not only No. 1 in all of television, it’s essentially Fox’s ATM. (Portfolio estimated it brings in $6.4 billion a year for the network.) And though ratings are down 12 percent since this time last year, it’s pretty much the only show that can consistently nab 25 million viewers. “It’s like if Alan Alda left M*A*S*H or Ted Danson left Cheers,” says Horizon Media analyst Brad Adgate. “How do you replace someone who’s the essence of why people watch?” (Fox and Cowell declined to comment.)

The snark-master certainly has viewer sentiment on his side, and season 7 finalist Michael Johns agrees, telling EW that Idol sans Simon would be like “a golf tournament without Tiger Woods.”

While Cowell has threatened to quit Idol before — even over seemingly minor matters, like the season 6 Sanjaya debacle — this time seems different. After seven years of intercontinental commuting between the L.A. Idol set and his London-based pet projects — The X Factor and the increasingly buzzed-about Britain’s Got Talent — the 49-year-old megamogul sounds exhausted. And he certainly doesn’t need the cash: Britain’s recent Sunday Times “Rich List” pegged his net worth at a recession-proof $175.2 million.

Moreover, he’s hinted that he’s itching to bring The X Factor to the U.S., which his current deal prohibits. But that’s hardly a surefire move. Yes, Cowell struck gold with AI and America’s Got Talent (for which he’s an exec producer). But remember the other reality shows he produced here? You know, American Inventor, Celebrity Duets, and Cupid? We don’t either. And the prospect of finding a new monster hit gets dicier every day, Adgate says: “That’s not an indictment of Simon Cowell — it’s more a comment on the TV landscape. I think there’s only one American Idol.”