What’s more pathetic, a retro-special about a 43-year-old show, or anticipatory nostalgia for a show that hasn’t yet ended? It’s a tough call, but I opt for the latter. Once again, NBC asks “Dateline” (8 p.m.) to hike up its hot pants and strut its stuff as a cheap hostess for the entertainment division. This time, they’re covering the “Frasier” finale as news. Two repeat episodes of “Frasier” will air at 7 p.m. and 7:30 p.m. While “Frasier” has been a Tuesday night comedy for some years now, it will air its last episode Thursday night, where it began in 1993.

Will we still care about “Frasier” in the year 2036? Can a comedy still draw viewers 43 years after its debut? That’s a question CBS must ponder as it presents “The Dick Van Dyke Show Revisited” (8 p.m., CBS). This now-classic sitcom first appeared in October 1961. It was a time of the “New Frontier,” and a young couple in the White House with a decided resemblance to Rob and Laura Petrie. America was aiming for the moon back then and packing off children to theme parks promising a “great big beautiful tomorrow.” I can’t imagine TV viewers from that future-oriented era sitting down to watch a “CBS Special” about a pop-cultural artifact from 1918, then 43 years in the past.

But the future isn’t what it used to be. Now our entertainment gaze seems fixed on an ever distant and continually recyclable past. Could this be the reason we’re beginning to run out of comedy resources?

Some folks have approached the end of “Frasier” and “Friends” as the death knell of the sitcom itself. Is that tragic? Or way overdue? After all, if you date the sitcom from the 1951 debut of “I Love Lucy,” that’s 53 years — one heck of a run. The “golden age” of radio didn’t last half that long. How long did vaudeville endure? But as both of those entertainment venues vanished they helped give birth to a fledgling medium called television. Not everybody was happy. Groucho Marx called TV “Terrible Vaudeville,” but something new and exciting was created. Maybe we should stop our nostalgic navel-gazing and embrace the new — whatever that happens to be.

Tonight’s other highlights

• The final four tackle disco music on “American Idol” (7 p.m., Fox). Don’t get me started.
• Jack exploits Saunders’ daughter on “24” (8 p.m., Fox).
• The Woodruff trial concludes, and so does the season, on “NYPD Blue” (9 p.m., ABC).

Late night

David Hyde Pierce and David Byrne appear on “Late Show with David Letterman” (10:35 p.m., CBS) … Jay Leno welcomes Pamela Anderson, Lance Burton and Clay Aiken on “The Tonight Show” (10:35 p.m., NBC).