Simon "I don't mean to be rude, but.." Cowell bids farewell to "American Idol" next week, leaving a litany of stinging put-downs, an assortment of black and white T-shirts and big shoes to fill on what began in 2002 as a summer talent contest and became America's most watched TV show.

"Simon's departure is the end of an era on 'Idol.' Everybody knows the show is going to lose something big and irreplaceable when he goes," said Todd Gold, managing editor of Fancast.com.

Cowell's exit as a judge from "American Idol" is more an "au revoir" than an "adieu" for American TV viewers. (He plans to return with his own "X-Factor" show in late 2011).

But the abrasive Briton and his one-liners have established a trend that has been widely imitated on US television.

"We had seen nasty people on TV both in fiction and nonfiction. But we had never seen anything quite like him before," said Robert Thompson, professor of popular culture at Syracuse University.

"It was almost when you put a panel together, you had to have certain types and one of those included the Simon character," said Thompson, recalling the arrival on US shores of Brits Piers Morgan ("America's Got Talent") and celebrity chef Gordon Ramsay ("Hell's Kitchen"), and Italian choreographer Bruno Tonioli ("Dancing With the Stars").

Whether he was rolling his eyes in exasperation, mocking fellow judge Paula Abdul, or introducing Americans to curious British expressions like "ghastly," or "a bit wet," 50-year-old Cowell was a breath of fresh air in the tried-and-true talent show formula, media watchers say.

He quickly became known simply as Simon, inspired a wave of T-shirts with slogans like "Simon Said I Was Good," and made "karaoke" a dreaded epithet.

"Simon dragged us into the reality that not every wannabe singer should be told to follow their dreams...It was a refreshing point of view that needed to be heard on US television," said Entertainment Weekly's Michael Slezak.