Listen up While network news flounders toward the future, the present belongs to NPR BY DAN KENNEDY

ANGST AND NETWORK news go together like — oh, like Simon and Garfunkel, whose popularity peaked around the same time that Walter Cronkite was signing off with the comforting fiction "that’s the way it is." For more than a quarter of a century, the audience for the three evening network newscasts has been both shrinking and aging — leading to widespread speculation that, someday, television news as we know it will cease to exist. Lately, though, angst has given way to full-scale, hyperventilating, stampede-the-exit-doors panic.

At CBS News, whose "Tiffany network" reputation has been little more than a bitter joke since the 1980s, Cronkite’s successor as anchor of the CBS Evening News, Dan Rather, was hustled into retirement in March. Rather’s departure came not long after he’d been harshly criticized by an internal investigation into last fall’s flawed 60 Minutes Wednesday report about George W. Bush’s National Guard service. His replacement, Bob Schieffer, is a capable, comforting presence; but he’s 67, looks at least 10 years older, and is no one’s idea of a long-term solution. CBS president Leslie Moonves has vowed to reinvent the newscast, and is bandying about ideas ranging from multiple anchors to a role for comedian Jon Stewart.

ABC News, the ratings and quality leader not so long ago, has been shaken to its core in recent weeks. First, Ted Koppel, anchor of the late-night news program Nightline, announced that he would leave at the end of this year. Then, Peter Jennings, anchor of the network’s World News Tonight, revealed that he has lung cancer and will need a substantial amount of time off while he’s undergoing treatment. Koppel, a brilliant interviewer, may be the only television journalist of his generation to rank with the likes of CBS legends Cronkite and Edward R. Murrow. Jennings — cool, deft, serious — has long enjoyed a reputation as the most cerebral of the network anchors.

Only NBC News appears to have weathered the anchor storms in good shape. Late last year the network pulled off a seamless transition from Tom Brokaw to Brian Williams on NBC Nightly News, and has maintained its lead in the ratings. Williams, 46, and the omnipresent Washington-bureau chief and Meet the Press host, Tim Russert, 54, are young enough to be around for a while. The news division can spread its costs across two cable networks (MSNBC and CNBC) and Today, which enjoys the best ratings of the three network morning shows. (CBS News, which lacks a cable outlet, has long been thought to lust after a deal with CNN. ABC News announced recently that it will launch a digital cable channel.) But even NBC is not immune from the long-term cultural changes and media trends that threaten the entire genre of network newscasts.

It’s true that, with as many as 30 million viewers tuning in to one of the three evening newscasts on a big news night, network news remains the closest thing we’ve got to a mass news medium. But according to Nielsen Media Research, only about 36 percent of households are watching — around half as many as a generation ago. Moreover, the networks insist on broadcasting their evening newscasts at 6:30 p.m., a time when most people are driving home from work (if they’re not still working), eating dinner, or helping the kids with their homework. The result: the average evening-newscast viewer is in his or her late 50s or early 60s, a demographic reality borne out by the ads for adult-incontinence protection, denture adhesives, and various types of medicine. "Without the prescription-law change 10 years ago" — that is, a change that allowed drug companies to advertise products available only by prescription — "these shows would have been gone," says Michael Socolow, director of the journalism program at Brandeis University and a former assignment editor for CNN.

Nor have viewers gravitated to PBS (The NewsHour with Jim Lehrer, admirably serious if duller than any television newscast ought to be, is shown at 6 p.m.) or the not-so-wonderful world of 24-hour cable news, which was originally touted as a news junkie’s dream come true. Compared with the network newscasts, cable audiences are tiny — even for the ratings leader, Fox News. Moreover, with a prime-time emphasis on talk over news (talk, you see, is cheap; news is expensive), the three major cable news networks — Fox, CNN, and MSNBC — are simply not a serious alternative to anything. CNN’s NewsNight with Aaron Brown has long been the closest thing to a network-level cable newscast, but lately it appears to be getting caught up in new network president Jonathan Klein’s obsession with "storytelling" (and ratings). MSNBC’s Countdown with Keith Olbermann has its moments, but the format (yes, it’s a countdown!) is contrived. And Fox’s prime-time line-up — The O’Reilly Factor, Hannity & Colmes, and On the Record with Greta Van Susteren — is a three-hour wallow in shouting and tabloid trash.

Thus, more than 50 years into the television era, television news is at a strikingly low ebb. The medium that defined the assassination of John F. Kennedy, the Vietnam War, and the first human steps on the moon has become an outlet for the elderly and the lonely. Yet broadcast news is actually as healthy as it’s ever been. It’s just that it’s gone low-tech.