In the 1980s, "The Cosby Show" was the No. 1 show on television for five years running, according to Battaglio. "All in the Family" had a similar five-year run in the '70s.
But "Idol" faces a challenge that neither of those sitcoms did. As Battaglio points out, it doesn't exist in a "three-network universe." Instead, the show competes with entertainment offered by the Internet and hundreds of cable channels, not to mention the slew of other reality shows that hit the airwaves this year during the Hollywood writers strike.
"Idol's" age is also working against it, Battaglio said. Just by being around so long, he said, it's turning younger viewers off.
"They're the most fickle and they're the ones who tend to drift away from things like this," he said. "They've been there and done that."
"It's only natural that after seven years," Battaglio said, "it's not the coolest thing to watch anymore."