DAYTIME TELEVISION is usually an afterthought, the industry’s ugly stepsister. Even for many who work in the business, soaps and talk are generally glimpsed only with the sound turned down as they dart through office lobbies.Yet the makeover of the nightly newscasts, CBS’ very public courtship of Katie Couric and the emphasis on low-cost programming all further a trend that’s been gaining momentum for some time — namely, the ascendance of daytime values, for good and mostly ill, across all of television. In the next few weeks, NBC will trot out a primetime gameshow, “Deal or No Deal,” for a trial run Monday through Friday, just as “The Price is Right” does mornings on CBS. And remember roller derby, the cheap stuff of weekend afternoons on local TV? A&E revives it in January with the slightly sensational title “Rollergirls,” highlighting an all-female team that blends jamming with equally bogus reality TV scenarios. Nightly news, meanwhile, yearns to be the morning news. CBS has determined that Couric is the kind of star the network needs to craft a different kind of newscast, just as ABC has introduced morning-style anchor teams on “World News Tonight” and “Nightline.” Mercifully, ABC’s promos for those shows don’t yet use first names the way “Good Morning America” does, perhaps because “See tonight’s car bombing footage with Terry, Cynthia and Martin!” doesn’t possess quite the same ring. PRIMETIME’S ON-AGAIN, off-again relationship with serials, another daytime staple, is also back on in a big way. Hell, even men have caught the fever, since what are “24″ and “Prison Break” really but just big soap operas with so much shooting and shivving there’s little time for screwing? The real mystery is why character-driven primetime soaps aren’t adopting daytime’s expedited schedules. “Melrose Place” and “Beverly Hills, 90210″ used to churn out 32 to 35 episodes a season, thus staying original much of the year. Master that formula and “Desperate Housewives” wouldn’t have to disappear from after Thanksgiving until the last college football bowl game has been played. Finally, there are those annoying daytime and latenight infomercials, represented in primetime by sponsored specials and brazen product-integration arrangements. All that’s missing is a guy in a loud jacket enthusing over how his vitamin supplement works wonders. Instead, we get Donald Trump shilling for advertisers, in loud hair. With audiences fragmented, it’s understandable why nets would embrace daytime’s “Do it fast, do it cheap” mentality, as well as personality-driven infotainment. At the very least, however, news divisions should advance cautiously, lest they discover that when it comes to standards, it’s sometimes darkest after the dawn. LOWER MATH: Amid the speculation surrounding Couric, it’s been frequently noted that morning TV is a greater source of revenue than evening news, which is an inane apples-to-oranges comparison. The three-hour “Today” block, after all, has six times the ad inventory of the higher-rated “NBC Nightly News” — the equivalent of comparing pro basketball and football gate revenues without acknowledging that one plays 82 regular-season games and the other 16. A second observation is that beyond CBS’ understandable instinct to roil the waters at NBC, Couric won’t travel well outside her current, cloistered environs. This is hardly a particular rap on Couric. CBS encountered a similar situation by bringing Bryant Gumbel to primetime with his short-lived newsmag “Public Eye.” More recently, Jane Pauley’s ill-fated foray into syndication proved that one of morning news’ best-loved icons couldn’t cut it on Oprah’s turf. Consider local news, too, where major anchor defections from one station to another seldom tow masses of viewers along with them. So while destabilizing “Today” is doubtless tantalizing, CBS might find by landing Couric that the net has simply traded in Dan Rather’s baggage for a star toting her own, albeit with snazzier accessories.