Simon was "just so jealous of me," Seacrest tells Entertainment Weekly.
"From Day One, he was envious of my career at such a young age," the "Idol" host says.
Now, without Cowell in the picture, "it's aged the show down a bit," Seacrest says.
"There are less clouds of smoke. We start earlier. There's less -- what's that English dish he always ordered for lunch? -- Shepherd's Pie."
Talking about the world order at "Idol" this season, Seacrest told the magazine that because Cowell had already done "Pop Idol" in Britain, the original cast -- including Paula Abdul and Randy Jackson -- took its cues from Simon.
"We learned a lot from him," Seacrest says.
After weeks of auditions, Lopez predicts "Idol" "may have the youngest winner ever."
"It's just astounding," Tyler added. "Some of them are 15 and look like they're 30. And some of them are 30 and look like they're 15."
Cowell was not available yesterday to respond. He was preparing his new show, an American version of the Brit hit "X Factor," for its debut here next fall, a spokesman said.