In its 12th season, the singing competition has slowed a lot. Last week, "Idol's" share of the local audience was 13 percent.
"It's clearly not what it used to be," said Ermish.
"Idol" was already in decline by Season 7 in 2008, but it averaged 26.4 million viewers per episode. In 2012, the show averaged about 15.9 million viewers a decline of 40 percent.
This season is down 47 percent from top-rated Season 5, which averaged 30.2 million viewers. The most-watched episode of Season 12 to date was seen by fewer people than the least-watched episode of Season 7.
"We expected this," said Fox Entertainment president Kevin Reilly. "It's not unusual for a show to lose audience as it ages."
But no one at Fox expected the viewership to fall from almost 18 million for the Season 12 premiere to an average of 12.3 million for the first three weeks of April. No one at Fox expected the April 18 episode to lose to a "Big Bang Theory" rerun nationally and in the local Utah TV ratings.
There are ramifications from this decline that reach all the way to Salt Lake City. If "American Idol's" ratings were what they were in 2008, it's a virtual certainty that KSTU-Channel 13 would have ridden that lead-in past KSL-Channel 5 in the late-news ratings during the February sweeps.
Local ratings impact • Television executives will tell you that lead-ins do matter. If the network programming that precedes a newscast is popular, that helps.
If not, well, KSL has been pointing to NBC's weakness as a reason for its big declines at 10 p.m.
KSL beat KSTU by a mere one-tenth of a rating point in the February sweeps. If local "Idol" ratings were as strong in February 2013 as they were in February 2012 they declined 43 percent that could have lifted Fox 13 into second place.
"I guess if 'Idol' was what it used to be, that probably would have happened," Ermish said. "But in fairness to KSL, NBC didn't give them much of a lead-in in February."
(NBC finished in fifth place in those sweeps, behind CBS, Fox, ABC and Univision.)
"Do I wish 'Idol' was stronger? Sure I do," Ermish said. "But it's in its 12th season. It's still a top-five show. I think there's still a lot of life in it.
"And I think Fox has more realistic expectations for it."
More competition • Fox's Reilly attributed part of the ratings decline to "not being the only game in town now."
For years, "American Idol" faced little competition in its singing-competition genre. But today, it is being challenged even outdone not only by NBC's "The Voice," but by Fox's own "The X Factor."
With former "Idol" judge Simon Cowell aboard, the two shows are virtually indistinguishable to many viewers. And, while "X Factor" has helped Fox's ratings in the fall, its arrival coincided with "Idol" ratings' steep declines in the winter/spring.
"Yes, there are too many of these shows on the air, probably," said Mike Darnell, Fox's president of alternative programming. "And they're all taking each other down a little bit."
Although, clearly, "Idol" is down more than "a little bit."
The judges • Fox's "Idol" strategy has clearly changed over the past 12 years. When the show premiered in the summer of 2002, the judges were two complete unknowns (Simon Cowell and Randy Jackson) and a has-been singer/dancer (Paula Abdul) and the show reached the height of its popularity.
Since then, we've seen big names (Steven Tyler, Jennifer Lopez, Ellen DeGeneres) in the judges' chairs and steep declines in ratings.
This season, Fox opened its wallet and is reportedly paying Mariah Carey $18 million, Nicki Minaj $12 million and Keith Urban $6 million. Returning judge Jackson is also reportedly making about $6 million.
Carey and Minaj created a storm of controversy with their ongoing feud.
And the show has fallen to its lowest ratings since Season 1, when viewership built from fewer than 10 million to almost 23 million for the finale which is 4 million more than the most-watched episode this season.
"It shouldn't be about any of us," Carey said. "It should be about the contestants."
But it isn't. If it were about the contestants, Fox wouldn't hire big-name, high-priced judges.
If it weren't about the judges, executive producer Nigel Lythgoe would not have told reporters just last week that a lack of "good chemistry with the judges" has hurt the show this season.
We know "Idol" will return in 2014. The question is which high-priced judges will be on the panel and how much lower the ratings will go.
"American Idol" airs Wednesdays and Thursdays at 7 p.m. on Fox/Channel 13.