Why she should reject the ABC World News anchor slot.

The nightly news broadcasts produced by CBS, NBC, and ABC may have become irrelevant to smart news consumers, yet the nation's dailies continue to pretend it matters who anchors the broadcasts. Yesterday's announcement that in four months Diane Sawyer will drop her butt into the seat currently warmed by Charlie Gibson inspired Page One coverage in today's New York Times and detailed reports in the Washington Post, the Los Angeles Times, and elsewhere.

But why? Let's see a show of hands in the Press Box audience: How many of you have watched the nightly news on ABC, CBS, or NBC in its entirety over the last month?

If you raised your hand, chances are you're collecting Social Security benefits. Last week, the three programs combined attracted an average of 20.3 million viewers a night, but most of them are old folks, creatures of habit and too infirm to change channels. Only 2 million people in the World News' audience of 6 million come from the coveted 25-to-54-year-old demographic.

Why the 63-year-old Sawyer would want to enter this dying news genre confounds reason—unless she's simply weary of rising in the early a.m. to appear on Good Morning America, which she's co-hosted since 1999. She obviously knows that the programs do less "real" journalism than they did in their 1960s-1970s heydays, when what they really excelled at was pointing to the headlines in that day's New York Times, Washington Post, Los Angeles Times, and Wall Street Journal.

As the network news audience has dwindled over the past three decades, broadcasters have reconfigured the shows as "infotainment" to boost ratings, aping the dreadful local news that they once disdained, says George Washington University media professor Mark Feldstein.

"The journalistic value of these programs is marginal at this point," says Feldstein, and the appointment viewing of tuning in to the nightly news at 6:30 or 7 p.m. is a "relic of the past." Feldstein, who has worked in TV news at NBC, ABC, CNN, and local stations, says that Sawyer's promotion won't change the underlying content of the show. Indeed, for all the noise made about Katie Couric's ascension to CBS Evening News anchor, her dismally performing show—an average of 5.4 million total viewers last week; 1.6 million in the 25-54 age group—has failed to distinguish itself in any meaningful way.

If the nightly programs add so little to our news diet and attract so few viewers, then why do they still air? Because they are very profitable, says Michael Socolow, an assistant professor in the Communication and Journalism Department at the University of Maine. In a forthcoming paper about network-news profitability, Socolow dispels the notion that the nightly news programs have ever been a civic-minded charity on the part of the networks. Back in 1969, NBC News' Huntley-Brinkley Report, which was No. 2 to the CBS Evening News' No. 1, generated $34 million in revenues on a budget of $7.2 million, making it the network's biggest source of revenue—bigger than Laugh-In or The Dean Martin Show.

That CBS News pays Couric—whose show trails a distant third in the ratings—a reported $15 million a year just to read the news gives you an indication of how lucrative these doddering franchises can be. The shows are still earning dividends from the Food and Drug Administration's 1997 liberalization of advertising rules for prescription drugs. Without that change, Socolow speculated in a 2005 Boston Phoenix feature by Dan Kennedy, the evening news shows "would have been gone." Spending on prescription-drug advertising now stands at about $4.3 billion and shows no sign of retreating.

According to a 2007 Philadelphia Inquirer piece by Gail Shister, ABC News was paying Charlie Gibson an estimated $8 million to anchor World News. Whatever they're paying Sawyer to replace him, it's too much. My advice to Sawyer is this: If you really want to improve World News, if you really want to make an indelible mark on journalism, turn down the job and persuade ABC News to divert the millions it ordinarily pays its anchor and spend it on 50 or 80 additional reporters to break stories.

But who will read the news on air?! I don't think it matters to the news or to the ratings who they put in the chair as long as that person is properly groomed and doesn't drool. That much was proved 42 years ago, when Walter Cronkite joined the American Federation of Television and Radio Artists' strike on the networks and the network called on a 28-year-old CBS lawyer and aspiring broadcaster named Arnold Zenker to replace him for two weeks. He did a fine job.