This is obviously, inspired by a past thread (https://www.sitcomsonline.com/boards/showthread.php?t=344869) on Fred Silverman's ill-fated tenure (https://en.m.wikipedia.org/wiki/Fred_Silverman#Move_to_NBC) as NBC's president and CEO (1978-81).

I'm sure that the first and foremost thing that most people will bring up (https://www.reuters.com/article/us-nbcuniversal-timeline/exiting-nbc-chiefs-blunder-timeline-idUKTRE68Q0AB20100927) is Jeff Zucker's handling (https://www.npr.org/templates/story/story.php?storyId=122623150) of the transition (https://en.wikipedia.org/wiki/2010_Tonight_Show_conflict) from (https://www.aol.com/news/2010-06-02-jeff-zucker-out-of-nbc-better-late-than-never.html) Jay Leno (https://www.spokesman.com/stories/2010/jan/14/one-time-nbc-whiz-kid-is-behind-the-leno-flip-flop/) to Conan O'Brien back to (https://www.latimes.com/archives/la-xpm-2010-jan-09-la-fi-ct-zucker9-2010jan09-story.html) Jay Leno on The Tonight Show (https://youtu.be/vBV-mm84rSI).

And not to get too political, but there's also the argument that Zucker played (https://www.nytimes.com/2020/09/20/business/media/jeff-zucker-helped-create-donald-trump-that-show-may-be-ending.html) a pivotal role (https://www.aljazeera.com/economy/2022/2/2/jeff-zucker-who-helped-propel-trump-to-power-resigns-from-cnn) in promoting Donald Trump's rise to power first through (https://www.independent.co.uk/news/world/americas/jeff-zucker-cnn-resigns-trump-b2006952.html) The Apprentice.

Beyond that though, there's the simple fact that under (https://www.salon.com/2012/11/29/cnn_hires_failed_gimmick_king_jeff_zucker/) Jeff Zucker (https://www.sfgate.com/entertainment/article/NBC-s-Jeff-Zucker-is-betting-that-ratings-2563508.php)'s watch (https://en.m.wikipedia.org/wiki/Jeff_Zucker#President_of_NBC_Entertainment), NBC went from being the #1 rated American TV network (https://buffalonews.com/news/networks-toss-programming-guidelines-to-the-wind/article_7d8625b0-d833-51cf-8221-e07f7c81ac11.html) to being (https://www.hollywoodreporter.com/tv/tv-news/five-ways-nbc-pull-last-54578/) dead last (https://www.nytimes.com/2005/05/16/business/media/mustsee-to-lastplace-tv.html) among the four major networks. There appears to have been way more misses (https://theweek.com/articles/493847/nbcs-jeff-zuckers-5-greatest-misses) than hits in prime time (https://www.thedailybeast.com/nbcs-biggest-prime-time-disasters) under his watch (https://www.forbes.com/2009/10/02/comcast-ge-nbc-business-media-zucker.html) as NBC (https://www.thedailybeast.com/nbcs-biggest-prime-time-disasters)'s entertainment president (https://www.chicagotribune.com/news/ct-xpm-2003-11-06-0311070050-story.html).

I think you basically nailed all the reasons he's so despised. But, I would also add the simple fact that he focused on quantity more than quality. He was happier airing five nights a week of "Deal or No Deal" or airing "supersized" episodes of "Friends" than actually working on developing new series.

In some ways it's unfair to blame him entirely; under his watch a number of high profile shows ended their runs (Friends, Will & Grace, Frasier) and just before he took over NBC they lost Seinfeld. I think anybody was going to struggle to replace that many huge zeitgeist defining hits; but man he really fumbled the ball.

Not to mention the incredibly stupid move he made cancelling "Law & Order" right before it was about to make history as TV's longest-running drama.

I think you basically nailed all the reasons he's so despised. But, I would also add the simple fact that he focused on quantity more than quality. He was happier airing five nights a week of "Deal or No Deal" or airing "supersized" episodes of "Friends" than actually working on developing new series.

In some ways it's unfair to blame him entirely; under his watch a number of high profile shows ended their runs (Friends, Will & Grace, Frasier) and just before he took over NBC they lost Seinfeld. I think anybody was going to struggle to replace that many huge zeitgeist defining hits; but man he really fumbled the ball.

Not to mention the incredibly stupid move he made cancelling "Law & Order" right before it was about to make history as TV's longest-running drama.

Also, NBC under Jeff Zucker's watch, wanted to have its cake and eat it too. I've already mentioned the Tonight Show conflict between Jay Leno and Conan O'Brien. But for those who don't exactly know what I'm talking about (https://www.resetera.com/threads/the-tonight-show-starring-jimmy-fallon-plummets-to-fourth-lowest-ratings-ever.362134/post-56429687), back in 2004, NBC essentially promised Conan The Tonight Show within five years as a means of persuading him to stay at the network. Apparently, Conan was on the verge of getting an insane deal from Fox.

Basically, Zucker told Jay that he would have to step down as host of The Tonight Show come 2009 even though he was still absolutely dominating late night TV. When I say that they wanted to have their cake and eat it too, NBC was afraid of losing Conan to another network but when the time finally came, they didn't want to lose Jay either. So NBC gave him that 10 p.m. show as sort of a compromise.

The OP basically stated most of the answers of why Zucker’s term was a failure. This topic has already been discussed but on The Tonight Show, O’Brien wasn’t pulling in the numbers and viewership dropped off and the network wanted Leno back and Leno wanted back. O’Brien ended up on TBS which didn’t have the ratings demand and he had a cult like audience but didn’t really have that much of a wide appeal, he did well enough but not well enough for a network.

I think if you look at the ratings from the 1950’s to the 20(00’s), CBS was mostly the ratings winner and the most dominant network and the other two (and later three) tries to up CBS, with some success, but would fall down the ladder. Network programming consists of a lot of hits and misses and gambles. It is a very difficult position, albeit a very well paid one.

NBC until the 00’s was my favorite network.