• by Wayne Friedman , Staff Writer, July 29, 2010

What causes the departure of a network programming chief? Surely, low-rated shows are a big factor; conflicting personalities can also be a  consideration. But most times it's a mystery. 

The departure of Stephen McPherson, president of ABC Entertainment, right before the start of the TV Critics Association meeting in Los Angeles could be a signal, that executives, like old magicians, will eventually run out of programming tricks. 

McPherson did give new momentum to ABC in 2004 when he arrived, what with  sudden hits from "Desperate Housewives,"  "Lost," and just a bit later, "Grey's Anatomy." While ABC competed for the top spot among key adult 18-49 viewers throughout his tenure, he could never get over Fox and "American Idol."   

Mind you, other competing network executives had the same problem. 

If you think it 's only about ratings, what can you make of Fox's ousting of Peter Liguori as its head of entertainment programming in spring 2009? Fox was on top -- after many seasons.  Maybe Rupert Murdoch was already thinking it couldn't last much longer -- that there needed to be an executive shuffling. 

Perhaps a key example of this mindset is what the NBC brass told Jay Leno in 2004: "Yes. You are on top now. But it's not going to stay that way. So, we're replacing you with Conan O'Brien -- in five years." 

NBC performed a similar move in getting Ben Silverman to run its prime-time programming, which resulted in the ousting of Kevin Reilly. The gamble was that Reilly had run his short course, and  Silverman was the future.  

Turns out both the Silverman and the Leno-O'Brien moves didn't predict the future.

All this points to some revealing tactics -- attempts to make changes before a big negative trend grips a network for the long term. The senior media executives whom programming executives report to -- especially those who ride herd over public companies -- always have to project a future vision, even if it seemingly sucks at the time.  That's what investors hear about.

While McPherson couldn't get over the initial big lift-off at the start of his reign at ABC, he had a pretty good second act -- adding on "Dancing with the Stars," and, last year, ambitiously launching an entire new comedy-heavy Wednesday night lineup. That resulted in award kudos for the likes of "Modern Family." 

So I'm guessing that Walt Disney chairman Bob Iger and Disney-ABC Television co-chair Anne Sweeney probably figured six years at the helm is a pretty good run -- but odds are things will probably get ugly real soon. Many network TV programming executives don't last nearly as long.

Of course there's personality stuff to consider. Liguori wasn't thought to have been close to Murdoch, which is a negative. The outspoken McPherson could be found having verbal tussles with competing network executives, as well as executives inside ABC. That isn't a plus either. 

That said, CBS seems to avoid such drama. CBS Corp. President and CEO Les Moonves seemed to instill loyalty and longevity, which keeps that network out of the press in this regard. 

But, for the most part, television programming is so fickle, so full of stuff that doesn't make sense, one can only assume any TV executive is only a phone call away from having his name attached to a press release touting his resignation, thanking those he worked with, and ending with the revealing phrase "leaving for new opportunities."