Jimmy Kimmel’s ascent to the main stage of late-night television — the hour directly after the 11 p.m. local news — was greeted last week with widespread congratulations for a performer who had paid his dues and for a network willing to shake up the late-night status quo and bet on a comedic challenger to David Letterman and Jay Leno.


But there was little outcry over the corresponding demotion of “Nightline,” the 32-year-old institution of ABC News that is being relegated to the 12:35 a.m. slot to make room for “Jimmy Kimmel Live,” nor any public denunciations from the hierarchy of ABC News.


Instead, the network’s appraisal that it simply can make more money with Mr. Kimmel — the president of the Disney/ABC Television Group, Anne Sweeney, evaluated the move in terms of an advantage in advertising sales — was accepted as both reasonable and sensible.


Several longtime late-night producers praised Mr. Kimmel’s talents, predicting he would find success, even competing against the entrenched titans of that hour, Mr. Letterman on CBS and Mr. Leno on NBC.


Lloyd Braun, a former ABC entertainment chief who selected Mr. Kimmel for the network 10 years ago, said: “Jimmy is young. He could have 10 or 20 years in late night — and he’s a brand. We’re going to live in a world where brands are going to mean everything.”


Tom Bettag, the longtime “Nightline” executive producer who now works with the former “Nightline” anchor Ted Koppel on “Rock Center” on NBC, expressed deep regret that his old show was being elbowed out of its perennial spot.


But, he said, “it had lost some of that indispensable quality” it had when first conceived by former ABC News president, Roone Arledge.


That quality was “Nightline’s” presence as the only national news on television after the network evening newscasts. With the growth of cable news, some of that value was inevitably lost, Mr. Bettag said. He added that it had become easier to uproot “Nightline” after Mr. Koppel left because “television is connected to personalities.”


He and other “Nightline” hands lamented what the move would mean to committed news viewers, and made the point that ABC’s plan — moving “Nightline” to 12:35 a.m., while adding an hour in prime time on Fridays — would inevitably be a hurtful and possibly fatal blow.


“Don’t be under any illusions,” one longtime ABC News executive said, asking not to be identified criticizing management’s decision. “They’re going to kill ‘Nightline’ with this move.”


The separation from late local news viewers will undercut the show’s relevance, the executive said, and the prime-time hour smacks of NBC’s ill-fated decision in 2009 to move Mr. Leno to prime time. “Prime-time shows get canceled — very easily,” the executive said.


How different it was in 2002, when ABC ardently wooed Mr. Letterman to defect from CBS and bring his show to the time slot occupied by “Nightline.” Then, ABC entertainment executives had to work secretly behind the news division’s back to chase Mr. Letterman.


When news broke that Mr. Letterman was being pursued, Mr. Koppel called a suggestion that “Nightline” was no longer relevant “at best inappropriate and at worst malicious.”


He met with Robert A. Iger, then president of the Walt Disney Company, ABC’s parent, to extract a promise that the network would remove “Nightline” only if it found an entertainment show of the highest quality that would provide significant financial benefit to the company.


Now chairman of Disney, Mr. Iger was, by all accounts, instrumental in deciding that Mr. Kimmel was now producing such a show.