Much like I did when the tsunami struck Japan earlier this year, I wandered around TV channels tonight as the news broke of Osama Bin Laden’s death to see which channels were offering coverage and for how long. And I noticed others on Twitter doing the same.

And then I wondered why I cared about which stations were staying on Bin Laden and which was leaving, as long as enough were staying.

CBS, which does not have a cable news sibling, remained on the news until 9 p.m. Pacific. Then, at least on the West Coast, the network cut away to primetime programming. NBC also cut away (“Celebrity Apprentice” with Donald Trump got to air, it should be noted), with MSNBC and Brian Williams taking control of its news coverage. ABC stayed on the news until 10 p.m., then went to “Desperate Housewives.”

This is obviously a judgment call in which pride mixes with financial considerations, where the need to tell the story mixes with the possibility that enough of the story has been told for the time being. There’s no law that a news update has to be endless – and to be sure, I’ve seen plenty of news updates on other stories in the past that went on much longer than necessary.

My original inclination is to be amazed that any network would cut away from a story this big with the news so fresh, the details still forthcoming and the reaction so vivid, but the more I thought about it, the less I begrudged CBS for its departure from the story. Viewers do have other channels to take in the story, so it’s not as if there’s a particular breach of duty, the way there would have been years ago in the pre-cable era.

The cost, of course, is that you don’t get to be the first name in news if you choose “Undercover Boss” over the end of Bin Laden. But if that’s no longer your goal, if news is merely a cog in your machine, so be it.

One thing the broadcast networks don’t seem willing or able to do is air live news coverage of such an event with commercial interruption – a compromise that would allow the news coverage to continue without the networks taking a revenue bath. But it’s not so simple to transfer a sponsor for “Amazing Race” to something much more amazing.

If you look at the killing of Bin Laden as a bookend to 9/11, though, the length of the broadcast network coverage didn’t back that up. But nothing was like 9/11, and hopefully nothing will be like it again.