Editor's note: David Bianculli is founder and editor of TVWorthWatching.com. He's a TV critic for NPR's "Fresh Air" and teaches TV and film history at Rowan University in New Jersey.
(CNN) -- First Keith Olbermann, now Glenn Beck: two highly vocal, aggressively opinionated TV commentators suddenly walk away from weeknight cable TV platforms. The question most often asked when such news hits -- as it did Wednesday, with the announcement of Beck's planned departure from Fox News Channel later this year -- is "Why?"
The better question, I suspect, is "What next?"
The "why," in both cases, is easy to surmise. Glenn Beck on Fox News (like Olbermann, before he and MSNBC put an instant end to "Countdown with Keith Olbermann" in January) is a media lightning rod. If lightning rods aren't grounded properly, they hurt more than they help -- and with the polarized and polarizing programs of both Beck and Olbermann, they were largely speaking to the converted.
This is a negative only if there aren't enough converted tuning in. In "All the President's Men," Deep Throat's advice was to "Follow the money." In TV, the best advice is to "Follow the ratings." If they're high enough, networks will forgive or overlook almost anything. When they dip, as Beck's have recently -- losing almost 1 million viewers in one year, when total viewership at his peak was less than 3 million -- networks can afford to make decisions based on other factors.
Behind the scenes, stories circulated that both Beck and Olbermann could be tough to work with -- a common charge aimed at those with strong viewpoints and an eagerness to innovate.
In a way, things haven't changed much since the '60s, when CBS, uncomfortable with the Smothers Brothers' increasingly political comedy and message on their popular prime-time variety series, fired them -- but only after ratings dipped considerably.
Beck's departure from Fox News seems more civil than Olbermann's parting with MSNBC, but in both cases, the networks appear almost grateful to be disconnecting their respective lightning rods.
But as one door closes, another opens. And what will matter most, to both Glenn Beck and Keith Olbermann, is where that new door leads.
The Smothers Brothers never again enjoyed the same sort of clout, or anywhere near as popular a platform. (Their CBS audience, at its peak, was 10 times larger than Beck's, and even greater compared to Olbermann's).
Beck and Fox, in a joint statement, said Beck would continue to develop projects for both the network and its online properties. That sounds like a much looser arrangement than the one between Olbermann and Al Gore's Current TV, where Olbermann plans to resurface later this year as both TV host and behind-the-scenes "news officer."
As pulpits go, both of these will be trickier for viewers to find -- Beck's, because his specials will be scheduled irregularly, and Olbermann's, because, well, it's on Current TV. You can count on both Beck and Olbermann to continue to rail against windmills and rant against adversaries. But if audiences don't follow or listen, did they ever really rant at all?
One very famous, though completely fictional, TV ranter -- with whom Olbermann, at least, is quite familiar, having cited him on many occasions -- is Howard Beale, the "mad prophet of the airwaves" created by Paddy Chayefsky in his classic 1976 movie "Network."
Howard Beale became an unexpected TV phenomenon by venting his anger on live television, yelling at viewers to scream, "I'm mad as hell, and I'm not going to take it any more!"
When I show the movie to students in my TV history classes at New Jersey's Rowan University, and ask them to identify modern-day Howard Beales, among the names that surface from this new generation are those of Beck and Olbermann. (Other names include Bill O'Reilly, Stephen Colbert and, most recently, Charlie Sheen, but let's not muddy things.)
At the end of the movie, Howard Beale had made enough enemies at his own network, and lost enough viewers, that the fictional UBS network decided to take action. But instead of firing or dismissing him, or issuing a joint statement of a parting of the ways, the UBS executives assassinated him. On live TV.
Viewed in that context, Glenn Beck, like Keith Olbermann, got off easy. But as they head through the doors to their next jobs, and their next platforms, getting their "mad as hell" viewers to follow might be tricky. And the size of their audience will determine the volume, and weight, of their voices.
The opinions expressed in this commentary are solely those of David Bianculli.