TIMELINE: Discovery at 25, 'Newhart' finale at 20

Belated anniversary wishes to two of TV's most memorable developments:

First, to Discovery Channel -- If you caught Sunday night's 25 Years of Discovery special, you know cable's original full-time documentary showcase is celebrating its 25th anniversary all this week at 9 p.m. New specials are spotlighting some of Discovery's biggest attractions. Note that I say "biggest" rather than best or most memorable.

That's because Discovery's salute includes Dirty Jobs: The Dirty Truth (Monday at 9 p.m. ET), Deadliest Catch/After the Catch (Tuesday at 9 p.m. ET), and MythBusters Top 25 Moments (Wednesday at 9 p.m. ET), for starters -- see a pattern here? They're all recent/current shows, and they're all emotionally structured or intensely edited docusoaps/demonstrations, not the histories or documentary explorations that built the channel's respected reputation.

Nobody expects Discovery to stay stuck on the model of its launch on June 17, 1985, but a little more attention to the original concept would be nice. True, the infant channel back then ran pretty much whatever it could pick up on the cheap from anywhere in the world -- but I happen to like discovering the history of Danish cinema pre-1927. And I absolutely loved offbeat pickups like Jonathan Ross' brawny cinema odyssey The Incredibly Strange Film Show, a British tribute series examining such low-rent auteurs as cult horror king Sam Raimi, nudie moviemaker Doris Wishman, and Mexican masked wrestler/action hero El Santo.

You never knew what you'd find on The Discovery Channel when you tuned in back then. But the lineup has become increasingly predictable as Discovery has joined the parade of cable channels twisting their niche mandates into pretzels to pursue mainstream ratings growth. Sure, Discovery still lines up jaws every summer for Shark Week. And they'll (co)produce a Planet Earth or a Life every now and then for "event" glory -- but they'll slap on "star" narration by a Sigourney Weaver or Oprah Winfrey to replace the original track by a certified natural-world expert like David Attenborough (whose British accent is apparently considered too off-putting to the American masses; I think that's called talking down to your audience).

I know the bills have to be paid, and there certainly may be a wider audience for the family feuding of American Chopper or the editing-juiced action of a Deadliest Catch. But what about the loyal fans of the original and, dare I say, more thoughtful channel? Where do they go when it morphs into yet another emotion-pumping star-driven ratings-chasing chameleon? (Don't say its spinoff Science Channel, unless you think endless airings of the perfunctory How's It Made explain the entire universe.)

At least this column's second anniversary celebrant remains unchanged. Of course -- since it was filmed, aired and frozen in time 20 years ago, on May 21, 1990, when CBS ended its run of Newhart.

That sitcom finale's final scene may be one of the most inspired pieces of series punctuation ever concocted. The small Vermont town where Bob Newhart's innkeeper tried to stay sane among the loony locals has sold its entire self to the Japanese. (Who were then expected to take over the world. Today's buyers would come from China.) Bob wakes up restless in bed from a confused sleep. He turns to tell his wife about this daffy dream -- and his wife is Suzanne Pleshette, from his previous 1970s Bob Newhart Show!

The moment was half Wizard of Oz and half St. Elsewhere in its dislocation, but it was also deliriously original, anchoring its punchline in two different series linked only by their titular star.

Take a look at the Newhart farewell (online here), then recall what Lost left us with. Newhart's end was in keeping with the series' content and tone, yet dared to extend and twist it into pop culture bliss. No yanking shamelessly on the heartstrings, or bloating to claim existential importance, or selling out half its own soul by neglecting to explain, well, pretty much the entire plot.

Okay, not a fair comparison -- comedy vs. drama, closed-end vs. serial -- but Newhart remains the gold standard of how to end a series with style, surprise and satisfaction. To paraphrase the old Sara Lee commercial, nobody doesn't like the Newhart finale.