Certainly, Zucker greatly underestimated the deeply ingrained viewing patterns of older Americans, who have always watched the networks in a particular way. The kids come home, do their homework, the family has dinner. They’re in front of the TV by 8, and 8:30 is known as the dog-walking slot. At 9, it’s time for more comedy. As they get tired, they like to watch a fictional drama that leads into the real drama of the late local news. And then they like to laugh again so that those images of war or a local murder are not the last thing they see before bed.

America has been watching a very specific sort of guy at 11:35 p.m. for half a century, one who chuckles as Mary Tyler Moore or Sarah Jessica Parker tells an amusing story and lets us drift off by the time some stand-up comic or blow-up starlet tells a salacious joke.

Zucker rolled the dice because he wanted to show Jeff Immelt that he could get beyond his Ben Silverman debacle and get prime time to stop bleeding money (a problem he created). But he learned the hard way that it is a lot to undo.

As Mark Harris wrote in New York magazine in November, “Zucker has often behaved like the grudging caretaker of a dying giant. ... As much as Jeff Zucker would like to cast the blame elsewhere, substituting number-crunching defensiveness for enterprise, adventure, and showmanship is what helped get NBC into this mess.”

Consumed with the NBC game of musical late-night chairs, Hollywood machers play a game of trying to figure out the last time there has been a blunder of such outlandish proportions. Despite everything, Zucker just got his contract renewed for three years with the Comcast acquisition of NBC. “Not since J. Pierrepont Finch in ‘How to Succeed in Business Without Really Trying’ has an executive failed upwards in so obvious a fashion,” marveled one TV writer.

Another called the Leno experiment the worst mistake made by anyone in television since an ABC Entertainment executive told the Chicago affiliate chief that the network didn’t want to own and broadcast the new daytime talk show hosted by a young black woman. Her name: Oprah Winfrey.