TV reboots have a rather sad history

AND LO, word went out from this place and time that NBC wants to reboot Angela Lansbury’s “Murder, She Wrote.”

Someone else wants to revive the millennial drama “Charmed.”

What we have here is, respectively, a bad idea and a bad idea.

Octavia Spencer, who would play the Lansbury role in “Murder,” is a fine actress. As for “Charmed,” it may be true that anything in a witch’s hat will draw a crowd these days.

These are still bad ideas, and no one should know it better than the TV biz, where the dirt is still fresh on the grave of the “Ironside” revival and they’re still hanging scented pine trees to mask the lingering fumes from last season’s updated “Charlie’s Angels.”

It’s true the revived “Hawaii Five-0” has reached season three. CBS has downshifted it to Fridays, though, and it has a much more modest presence now than it did back in the day.

The revived “90210” followed a similar pattern, starting in 2008 with 4.65 million curious fans and vanishing in 2013 with 500,000.

And those are the winners.

More typical of reboots was the second “Melrose Place” (2009-2010, the CW) which barely made it through one season. Just like the second “Knight Rider” (2008-2009, NBC).

The second “Bionic Woman” (2007, NBC) was euthanized after eight episodes by the writers’ strike. The second “Get Smart” (1995, Fox) didn’t last that long.

Remember the second “Love Boat” (UPN, 1998-1999)? You’re not alone.

Last season NBC aired a few episodes of “Mockingbird Lane,” a contemporary reimagining of “The Munsters.” It vanished like a bedroom monster at dawn.

Even PBS couldn’t make rebooting work. Its beloved “Upstairs, Downstairs” returned in 2010 and limped through two seasons before everyone decided it was not PBS’ best idea ever.

We do know why television keeps making reboots. Same reason it keeps making spinoffs.

It’s so hard to score a hit that if you can launch a show with any advantage, like a little happy history or brand recognition, you know that can’t be bad.

Also, on paper, reboots should work. Classic Broadway shows get revived all the time. Great songs are reinterpreted. Many great movies have been made two or three times.

TV turns out to be different, though it’s tricky to pinpoint exactly why.

Maybe TV viewers get more attached to actors. Splendid as Blair Underwood is, he couldn’t completely duck the “Ironside” shadow of Raymond Burr.

When a “Rockford Files” reboot was wisely scrapped a couple of years back, you know part of the reason was the shadow of James Garner.

That’s also the biggest fear with “Murder, She Wrote.” You think about that show, you envision Angela Lansbury.

Maybe more important, though, TV shows are of their time. They work because the combination of story, actors, look and style fits a moment — from “I Love Lucy” to “All in the Family” or “Cheers” right up to “Modern Family” and “Big Bang Theory.”

You can dust off the bottle, but the second time it may not catch the lightning.

Which doesn’t stop the TV biz. Even as we speak, someone in some meeting somewhere is saying, “We’ll always have ‘Dallas.’”