Back when Howard Cosell was doing “Monday Night Football,” I used to say I watched the game with the sound turned down. You said it, too. Admit it.

I never turned the sound down; neither did you. Admit it. But if you’re a fan who’s been watching this season, you’re reaching for the remote. Admit it.

It’s time to acknowledge that, not in spite of but largely because of Cosell’s intelligence and abrasiveness, ABC’s “Monday Night Football” became a vital cultural touchstone, transcending sports and approaching the level of, say, the Ed Sullivan Show from the late 1950s through the mid-1960s in importance. This comparison has more to recommend it than you might think. Ed Sullivan, like Cosell, came from a sports background, and Cosell, like Sullivan, always wanted to host a TV variety show, and actually did for a while. Sullivan’s show and MNF were similar in another way: No other long-running primetime TV show featured visits from athletes, opera singers, movie stars, and rock musicians. But even Sullivan could not have envisioned so bizarre a convergence of disparate icons as John Lennon and Ronald Reagan on the November 26, 1973 telecast. (When they cut back from a commercial, you could actually hear a few seconds of the Gipper explaining American football to Lennon.) Of course, that’s back when the mass audience existed for prime time network broadcast sports.What would the equivalent of Cosell-Lennon-Reagan be today? Bob Costas-Bono-George Bush? Possibly, but you’d never see them all together at a football game.

It shouldn’t be necessary to point out that the decline of the show’s popularity is far from a phenomenon confined to sports. This year, the Miss America Pageant appeared before its last natural constituency on County Music Television. It’s only a matter of time before the Academy Awards are bumped to A&E, or possibly even E! Except for the Super Bowl and maybe the NCAA Men’s Basketball Tournament — both of which, because of office pools, are watched by people who otherwise have little interest in sports — televised sports have become comparatively marginal since the heyday of “Monday Night Football.” The availability of so many entertainment alternatives has splintered the audience into a host of small groups, many of which are growing up with no connection to sports.

There’s no way now to suggest to a younger generation the kind of impact that “Monday Night Football” had for nearly two decades. Even when you didn’t particularly care who was playing, even when Cosell left after the 1983 season, followed a year later by the oddly endearing Don Meredith, there was still something comforting about being in a public place — an airport lounge, a shopping mall with a TV in the department store window — and seeing a diverse group of people watching and talking about the game. In contrast, the new “Monday Night Football” on ESPN is like watching a made-for-TV remake of one of your favorite movies.

To be fair, this is partly because the game has changed, and not, if you really like football, for the better. Rosters have expanded so much that the versatile, multi-skilled player has practically vanished. My own favorite position, middle linebacker, the one usually played by the most savage tacklers, like the Packers’ Ray Nitschke and the Bears’ Dick Butkus, scarcely exists anymore.

The coaches don’t stand out, either. Years ago, when the camera flashed on Vince Lombardi, you recognized his tan topcoat and brown fedora instantly, as you did with Tom Landry’s blue blazer and pearl gray hat. They’ve been replaced by a committee, anonymous in their NFL apparel with their faces obscured by huge, wireless headsets.

The tip-off that “Monday Night Football” was dying as an institution was the hiring of comedian Dennis Miller in 2000.Some venal-minded executive who is probably now selling Pepsi apparently thought Mr. Miller would be a Cosell for a new generation.He couldn’t have been more mistaken. Cosell was egotistical, while Mr. Miller merely narcissistic. Mr. Miller didn’t clash with his colleagues and create sparks like Cosell, he didn’t connect with them at all. Or the audience. Or anyone except himself.

If Mr. Miller stood out like a broken thumb, the current trio doesn’t stand out at all. Play-by-play announcer Mike Tirico, who spent years as a golf commentator, is smart, pleasant and nondescript. He’s exactly what you’d get if you took every broadcaster in sports and averaged them out. Color commentator Joe Theismann is a repository for every sports cliché of the last four decades. Here’s two observations made within 10 minutes of each other during the Green Bay-Philadelphia game a couple of weeks ago:

“When you have a young team and you get great field position, you have to take advantage of it.” (Old teams presumably, do not have to take advantage of great field position.)

And, “When you’re a young team, you have to take advantage of opportunities.” (Middle-aged teams, presumably, do not.)

What is amazing about Mr. Theismann’s commentary is not so much its banality as the conviction with which he says everything. He really seems to think he is the first person to air these commonplace inanities. More irritating still is his habit of constantly making excuses for poor player performance. Say what you want about Cosell, but he would have tolerated the likes of Thiesmann for about 10 minutes before chewing him to pieces.

The show’s worst idea, however, was the decision this year to hire Tony Kornheiser, a former ESPN rant show host, as the second color man. I have yet to hear Mr. Kornheiser make a single comment pertinent to anything happening on the football field. A typical irrelevancy pulled from the New Orleans Saints-Atlanta Falcons game, after Mr. Theismann had discussed Reggie Bush’s success in the West Coast offense: “I don’t know much about the West Coast offense, but I know star power, and Reggie Bush has it.”

Together, the three of them are so numbingly dull that you may tell yourself to turn the sound down and then forget that you didn’t. More than likely, though, you’ll have hit the channel changer before the mute button.

Mr. Barra is the author, most recently, of “The Last Coach: A Life of Paul ‘Bear’ Bryant.”