Sooner or later, every expensive thing finds itself supplanted by some technology-driven thing that’s cheaper: Ivory billiard balls were replaced by plastic, silk by nylon, mainframes by desktops, your local recording studio by GarageBand, and so on. Ivory, silk, mainframes, prestigious recording studios, and other luxury-class goods survive, but cost-cutting technological advances have steered them into niches.

That’s precisely where Web video news producers intend to steer broadcast and cable news – into niches. And they’ve got a shot at it. In 1980, CNN began exploiting the falling costs of broadcast gear and satellite time. By decade’s end the upstart network had not only equaled the traditional broadcasters but exceeded them, becoming the vital source for breaking news. Fox News Channel and MSNBC provided the next lesson by adapting talk-radio culture to cable news. Now, falling bandwidth prices, incredibly cheap video gear and ubiquitous smartphones  – 45 percent of American adults own one – lend similar economic advantages to those looking to displace cable.

One new news-and-information prospector is Huffington Post co-founder Ken Lerer, who this week bestowed a name on the cable-news slayer he has been assembling in his skunk works since last spring: NowThisNews, shooting for a late-October launch. As AllThingsD reporter Peter Kafka reports, NowThisNews will chart a different path than its fellow video pioneers at HuffPost Live, namely 12-hour blocks of talk-show chat. Lerer promises “short video pieces that will hopefully be very viral and very social, one at a time.” His general manager, Eason Jordan, a CNN veteran, told Kafka: “There’s an abundance of talk. We intend to report the news.” As distribution partner, Lerer and company have enlisted click-whores (and I use that term with complete admiration) at BuzzFeed, which will also assist in the creation of NowThisNews’s clips.

The Web-news thicket that NowThisNews is entering is so densely populated, an army of hackers launching a thousand DDoS attacks couldn’t clear it. Practically every legacy media operation (online services, TV networks, local TV and radio stations, daily newspapers and wire services) boasts a Web-news adjunct that both repackages old reports and streams original material. Native-to-the-Web operations such as Slate, Talking Points Memo, SB Nation, Glenn Beck’s TheBlaze TV, SB Nation, and others have aggressively applied their news-info talents to the screen. Viewers who get Al Jazeera (or other foreign broadcasters) on their cable systems can often stream it on the Web or download an app for their smartphone.

The baby steps of HuffPost Live, which debuted in mid-August, demonstrate the challenges of making watchable video. At its worst, HuffPost Live resembles a “karaoke version of what’s on cable,” as my Reuters colleague Sam Jacobs puts it. Its telegenic, young anchor/hosts mouth journalistic lyrics to match the backing tracks of their interview subjects, who appear in the flesh or via Webcam. It’s such a bush league venture right now that Monday, when American Idol judge Randy Jackson dropped by HuffPost Live to talk about diabetes, he volunteered that the music that preceded his segment was “low level, really cheap, inexperienced, student film music that you found extremely free somewhere – not just free, extremely free, like somebody please take this music!”