ALTHOUGH CBS IS understandably proud of its across-the-board November sweeps victory, that milestone also represents a minor breakthrough for a group the networks and advertisers have conspired to bury.Call it “Revenge of the 50-Plus Audience.” For years, CBS’ reputation as the alter kocker network reinforced the impression that programs likely to score big among the Dentu-Grip set were an automatic turnoff to young-adult demos. Conventional wisdom stated that 18- to 34-year-olds wouldn’t watch “Murder, She Wrote” and “Diagnosis Murder” except by accident — say, during a visit to grandmother’s house. Pundits (OK, me) joked that CBS shows skewed so old characters were forbidden to applaud for fear of inadvertently clapping off sets. Yet dissecting sweeps results, a funny thing happened on the way to the retirement village. CBS ranked first among adults age 18 to 49 while retaining its commanding advantage among those 50 and older. Despite hyperbolic exclamations about rediscovering Ponce de Leon, that older group provided the lion’s share of the network’s 3.5 million total viewer margin — the widest sweeps gap since 1987. Moreover, even with CBS’ newfound success in the demo derby, the 50-plus bracket accounted for fully 52% of its primetime audience. That compares with 44% and 40% at any given minute for NBC and ABC, respectively, which tied for second in the key young-adult demo. As for Fox, a mere 26% of its tune-in was 50-plus, a youthful tilt that didn’t spare the network from a fourth-place demographic finish. Perhaps the moral here, given Fox’s over-reliance on unscripted fare this fall, is that people 50 and up are more likely to be a big fat obnoxious boss than waste time watching one. WHAT THIS ULTIMATELY MEANS is that despite the prevailing sense of TV splintering into narrow demographic pods that can’t dance together, certain programs are bridging the disparity between old and young. Prime examples are ABC’s “Desperate Housewives” and CBS’ “CSI,” with the latter roughly tripling the audience for “The Apprentice” in 55-plus and still handily surpassing NBC’s corporate survival contest among younger adults. This isn’t to suggest age doesn’t represent a point of demarcation. Fox News Channel, the No. 1 cable network among adults 50-plus, ties for 28th within the 18-34 age bracket in primetime. Not surprisingly MTV, No. 2 by that latter measure, is barely a blip among those born before the Eisenhower administration. Cultural historians should view the older crowd generously in this regard, inasmuch as they have collectively treated the most odious elements of so-called reality TV with at best confusion and at worst contempt. That those over 40 consistently favor “The West Wing” and “Nightline” over “The Bachelor” and “The Swan” might not qualify them as the greatest generation, but at least they possess more discriminating taste than their juniors do. SO WHILE NETWORKS chase youth and Madison Avenue steadfastly continues to resist paying to reach those over 50, the good news is it doesn’t follow that oldsters must flee to Turner Classic Movies to find entertainment. And as corny as it sounds, that means the traditional concept of broadcasting isn’t a complete anachronism — proving it’s possible for networks, at least, to occasionally act as a uniter, not a divider. At the same time, sweeps figures also reinforce a key rationale marketers cite to justify their intense devotion to younger demos, with data clearly indicating that older adults watch far more television than younger counterparts. This is significant because media buyers and therefore networks are as illogical as the rest of us — most coveting those who play the hardest to get. In other words, people, if you want some long-overdue respect, stop being such good customers. Oh yeah, and promise to stick around buying cars and beer for the next 40 years. Advertisers like that about 18- to 34-year-olds, too.