For broadcast networks, the evening news broadcast is a cherished part of their legacies — having brought the likes of Walter Cronkite, Tom Brokaw and Peter Jennings into living rooms over the decades.

But with pressures mounting on the traditional TV business, the American institution is in a period of flux.

The traditional TV audience is a slow melting glacier, with network evening newscasts down nearly 1 million viewers in the 2024-25 season compared to the previous year, according to Nielsen. As a result, network news executives will be on edge this year, with two of the three broadcasts undergoing major overhauls.

Next month, NBC will replace longtime “Nightly News” anchor Lester Holt with Tom Llamas, 45, who helms the streaming NBC News Now program “Top Story.” It will mark only the fourth change in the “Nightly” role since 1983.

This comes after “CBS Evening News” in January replaced Norah O’Donnell with a duo of John Dickerson and Maurice DuBois. Conceived by outgoing “60 Minutes” executive producer Bill Owens, the new “CBS Evening News” has aimed to do longer segments instead of the headline-driven style the broadcasts are known for.

Although broadcast networks have largely ceded scripted TV shows to streaming, they are still protective of the news programs. Both NBC and CBS are trying to improve their competitive position against “ABC World News With David Muir,” which has its largest lead over the second-place peacock network in 30 years.

Like other TV newscasts, evening programs are in a battle to maintain relevance amid competition from not only cable and streaming but also YouTube, which attracts older audiences as well as younger, digital-savvy viewers.

“No one wants a tombstone that reads ‘Here lies the guy who killed the evening news,’” said Jonathan Wald, a veteran producer who worked with Brokaw on “NBC Nightly News.”

Evening newscasts on ABC, CBS and NBC — all of which launched in the late 1940s — are among the few shows that still drive appointment viewing.

They’ve held up better than most TV network genres. Nielsen data show the programs are watched by an average of 18 million viewers a night and reach 71 million each month despite competition from 24-hour cable news and a barrage of platforms available digitally.

There are many weeks throughout the year when Muir’s broadcast is the most watched program in all of TV, often averaging 8 million viewers.

So far, the audience isn’t buying the changes on “CBS Evening News.” The program has dropped below 4 million viewers in some weeks since its launch and occasionally gets topped by “Special Report With Bret Baier” on Fox News.

NBC News executives believe Llamas can provide a fresh spark for “Nightly News.” They’re encouraged that he led in the 25-to-54 age group on recent nights when he filled in for Holt.

“We think he’s exactly the right guy at this moment,” said Janelle Rodriguez, executive vice president of programming for NBC News. “He is someone who has worked at this literally since he was a kid.”

But there is always risk involved when an anchor change occurs — programs typically see a shift of 500,000 viewers in the aftermath. A single audience share point decline in the Nielsen ratings can mean about $10 million less in ad revenue.

Evening news broadcasts are still profitable businesses and have benefited from increased advertiser demand for audiences watching live TV. In 2024, ad spending on the three network evening newscasts, including the weekend editions, hit $669 million, according to measurement firm iSpot.tv, an increase of 12% over the previous year.

The programs also still provide an identity for ABC, CBS and NBC. A recent study by research firm Magid found that 50% of consumers cite news as their top reason for watching a network TV affiliate.

Most of the people tuning in at 6:30 p.m. to watch are older viewers who likely grew up with the habit, as evidenced by the commercial breaks. The data from iSpot show around 46% of the ad dollars spent on the programs are for pharmaceutical products.

Competitors have long taken shots at “World News,” calling it a shallow broadcast that delivers a lot of of stories without much detail. ABC News executives counter that Muir has traveled around the world to do lengthier reports that are expanded into documentaries for Hulu.

“We spend a lot of time making sure the show is informative visually and reflects a modern, elegant broadcast,” said Chris Dinan, Muir’s executive producer. “David knows television. He’s a student of it.”

Viewers, who like Muir and the visual sizzle of “World News,” have made it No. 1 for nine consecutive years.

“You can’t listen to the chattering classes,” said Wald. “The show is watchable and consistent. You know what you’re going to get.”

Muir’s success has been rewarded. After sharing special coverage anchor duties with George Stephanopoulos, he is now the dominant face of ABC News. Muir’s former longtime executive producer, Almin Karamehmedovic, became president of the division last year.

For most of his tenure, Muir has maintained a neutral image that protected him from right-wing claims of bias made against many mainstream journalists.

That changed last fall as Muir and colleague Linsey Davis became targets after they vigorously fact-checked President Trump at the second presidential debate in September. “I’m not fans of those guys anymore,” Trump said during a Fox News appearance. “And his hair was better five years ago.”

Trump’s anger at Muir has had no impact on the ratings for “World News,” which have remained steady. Nielsen data show the program’s audience is down only 1% in the 2024-25 TV season compared to a year ago, while “NBC Nightly News” is off 6% and “CBS Evening News” is down 8%.

While Holt’s departure from “Nightly News” was presented as his decision, NBC News is historically unsentimental when it comes to making talent transitions, always looking for the next generation.

Llamas, 45, has spent three years at the helm of “Top Story” on NBC News Now, the network’s 24-hour streaming news service that draws a younger audience than the broadcast network.

Like Muir, Llamas has been immersed in TV news since he was a teenager.

Muir worked in a local Syracuse TV newsroom where staffers tracked his growth spurt with pencil marks on a wall. A 15-year-old Llamas landed an internship at a Miami TV station with the help of Jorge Ramos, the longtime Univision anchor. (Ramos’ children were patients of Llamas’ father, who has a dental practice in Miami.)

Llamas interned at “NBC Nightly News” and went on to jobs at MSNBC and as a local anchor at NBC’s Miami and New York stations. He moved to ABC News in 2014, where he was anchor of the weekend newscast and often filled in for Muir. He returned to NBC in 2021, leading to immediate speculation that he was being developed as Holt’s heir apparent.

“He’ll be a great steward for what ‘Nightly’ is now and maybe even extend its lifespan by injecting some youth,” said Wald.

The question at CBS News — which has been distracted by a lawsuit filed by Trump against “60 Minutes” and the pending sale of parent company Paramount Global to Skydance Media — is whether it will make tweaks to its evening news format before viewers start sampling again after Holt departs.

“CBS Evening News” co-anchors Maurice DuBois, left, and John Dickerson.

(Gail Schulman / CBS News)

CBS News declined to provide an executive to speak on the record about the newscast. But two people close to the show said management continues to support the alternative approach to the broadcast and there are no imminent changes.

People who work on “CBS Evening News” but were not authorized to comment publicly said the program has already moved to shorter pieces. The producers are also expected to get some notes from Tom Cibrowski, the new CBS News president who comes from ABC News, where there is an emphasis on being viewer-friendly.

But the challenges faced by CBS demonstrate how hard it is to make changes to evening news when continuity and familiarity matter to the audience.

Muir was a longtime weekend anchor and then primary substitute for Diane Sawyer during her five-year run on “World News.” Holt was a fill-in for Brian Williams before his abrupt departure in 2015.

CBS has likely been hurt by changing evening news anchors six times since Dan Rather ended his 20-year run at the desk in 2005. The program has long suffered from a weak audience lead-in from its local stations, a problem that goes back to the mid-1990s, when a number of its affiliates switched to Fox after CBS lost its NFL package.

But broadcast networks are aware that the downward trend in appointment viewing on traditional TV is never going to reverse. It’s why the networks have expanded their evening news programs online.

Llamas will continue to do “Top Story” on NBC News Now after he takes over for Holt in June. Dickerson has done an additional half-hour, which includes a longer newsmaker interview and a brief commentary at the end, on “CBS Evening News Plus,” which is shown on CBS News Streaming after the network broadcast.

All of the evening newscasts stream full episodes on YouTube, each attracting several hundred thousand viewers a night, as well as getting repeat airings on the 24-hour streaming news channels. “NBC Nightly News” clips reached 43 million on TikTok in the first quarter of 2025.

“As people move across different distribution points, we need to be ready for them,” Rodriguez said.