Where have the family dramas gone?

As “7th Heaven” vanishes, viewers may be wondering: Whatever happened to family dramas? Weren’t they big once?

They were.

According to the 2003 edition of “The Complete Directory to Prime Time Network and Cable TV Shows,” “Lassie” ran 17 seasons, “Bonanza” 14, “The Waltons” and “Little House on the Prairie” nine each.

All were centered on families. So, in a perverse way, were “Dynasty” (eight years) and “Dallas” (13).

Many of them soared. “Bonanza,” “Dallas” and “Dynasty” all reached No. 1 in the annual Nielsen ratings; “Waltons” was No. 2, “Little House” No. 7.

There have also been dramas that weren’t really about families but were aimed at them. “Touched By an Angel” lasted nine years, four of them in the top 10.

Then such shows vanished. Some recent ones – “Joan of Arcadia,” “American Dreams” – started well, then faded.

These days, about the closest you get to family drama is when, during a recent episode of “Alias,” a father told his daughter to keep her gun aimed at her mom.

Among the reasons for the trend:

Separate sets: TV shows have a harder time getting everyone into one room.

Kids might start out watching Nickelodeon, then Disney Channel as tweens, and MTV as teens. Their parents can watch interchangeable “Law & Order” reruns and James Bond movies. It’s hard to get everyone watching the same thing.

Reality replaces: Actually, a few shows do draw mixed audiences. “American Idol” has become universal; “Extreme Makeover: Home Edition,” “Survivor” and “Amazing Race” all draw broad crowds.

You could call them dramas, but no one mistakes them for “The Waltons.”

Cable confusion: Family dramas exist on cable, but not in the usual way.

“The Sopranos” has a crime family, at work and at home. “Huff” has angst and anger. “Big Love” has lots of warmth, but only one husband for the three wives.

For all of its dysfunction, “Six Feet Under” may have been one of television’s most textured family shows. Now it’s gone, too.

The WB wobbles: In recent years, the WB network has pushed the hardest for family dramas. Along with 10 years of “7th Heaven,” it has had moments of brilliance from “Everwood,” “Gilmore Girls” and “Related.”

The network, however, has been in a general slump lately. In September, it will merge with UPN, turning two networks into one.

Observers have predicted that “Gilmore Girls” will reach the combined network, but “Related” won’t and “Everwood” is iffy.

For now, viewers may have to be content with tidbits of family life.

There are full families in “Medium” and “Commander in Chief” (the latter also facing an uncertain future after being pulled off the air during May sweeps month).

There are parents and kids – albeit combative ones – on “Desperate Housewives” and “The O.C.” There are families in “Invasion,” even if some of the grown-ups did become alien hybrids.

And Clark Kent had a warm, loving relationship with his parents on “Smallville.” Then the WB killed his father.

Family dramas can’t be arbitrarily created, says “7th Heaven” star Stephen Collins.

“It’s got to come from someone who believes in it – someone like Earl Hamner with ‘The Waltons,’ or Brenda Hampton,” Collins says.

Hampton created “7th Heaven” and stayed with it for the entire decade. At first, she admits, she was scrambling.

“The first year of the show, none of the writers had children,” Hampton says. “I think we were writing it for our cats.”

Still, she believed in it and got the hang of it. But that doesn’t mean she’ll get to do it again.

“I would think the networks would want to buy another family show from me,” Hampton says. “I’ve had 10 years of success with this one.

“But … I pitch family shows and networks just go, ‘Uh, I don’t know if there’s a market for them.’ “