Piers Morgan (Mario Anzuoni/Reuters)

One way that cable news differs from more traditional news providers — newspapers, for example — is cash. They make a lot of it, that is. We hear that Fox News tallies net profits in the range of $1 billion. The comparable number for CNN has been reported as $600 million (the figure includes the company’s various channels and Web sites). Hey, even the dismal-ratings-achieving Current TV, in the words of founder and former chief Al Gore, was “profitable each year” and sold out for a princely $500 million.

With all that money flowing in, cable networks surely are moving to greater and greater amounts of enterprise journalism. They must be stacking their programming schedules with more resource-intensive live coverage and investigating more stuff.

Wrong, according to a study by the Pew Research Center’s Project for Excellence in Journalism.

A couple of the key findings:

Interview segments are now as prominent in daytime cable as they are in prime time. Coverage of live events and live reports dropped in daytime programming by about one-third—from 33% of the newshole in 2007 to 23% in 2012. And the airtime devoted to interviews rose from 39% to 51%, equaling the percentage of airtime they fill on cable at night, when partisan talk and debate drive the programming.

In 2007, CNN spent far less time airing interviews and far more time running edited packages than either Fox or MSNBC on prime time. But that had changed markedly by 2012. The percentage of CNN evening programming filled with interviews jumped from 30% in 2007 to 57% in 2012. At the same time, the airtime for edited packages plunged from 50% to 24%

Interview programming, of course, is the ramen of cable news. You put a camera in front of some volunteer commentator and get a bunch of chatter for free. Or you put a camera in front of some newsmaker — again, free of charge. Or you put a camera in front of a paid contributor whom you work to death day and night and weekdays and weekends. (Note: MSNBC’s prime-time coverage presents a counterexample to the trend, as its “package” tally shot up from 13 percent to 31 percent over the course of the study).

Such reliance on cheap content may well go a long way toward explaining cable news’s glorious bottom line, not to mention its addiction to the extensive Internet pass-around that explosive, shout-laden interviews tend to prompt. Disclosure: The Erik Wemple Blog dutifully feeds that addition.