Why do good shows get cancelled, and can we save them? The answer to the first question is always the same: Low ratings, although it’s more complicated than that.

Sometimes, studios and networks clash over the creative direction. Before you can say “show killer,” you’re on Friday night without a penny in promotion.

The TV business has become like the movie business: If you don’t open big, you’re dead. And since the only shows that open big anymore are inexpensive reality shows, why waste millions trying to develop the next Friends or Frasier?

That’s what NBC has finally decided, with The Apprentice finale beating CSI last Thursday night.

However, there’s just too much money to be made on scripted shows when they’re sold into syndication.

Twenty to 30 years ago, with less competition, networks could afford to be more patient. NBC waited over a year for Cheers, Hill Street Blues and St. Elsewhere to find audiences.

Some of TV’s most-loved sitcoms, including The Dick Van Dyke Show, All In The Family, The Mary Tyler Moore Show and even Seinfeld were slow starters.

A show such as Arrested Development deserves to be added to that list. It is consistently funny and original, yet has failed to find a large audience this season Sundays at 10:30 p.m. on Fox (22).

Can fans save a show like Arrested Development?

This time of year, with just weeks to go before fall schedules are announced (May 17 to 20), dozens of Web-driven Save Our Show campaigns are launched. Some actually work.

A few years ago, Roswell fans sent UPN executives 12,000 bottles of Tabasco sauce - a favourite food of the show’s aliens - when that show was on the bubble. UPN ordered a second season.

Some shows have survived by switching networks.

That’s the tactic Angel fans are taking. There is word that producer Joss Whedon is trying to shop the show, cancelled by The WB, to UPN. That same move worked for Whedon before with Buffy The Vampire Slayer.

Switching networks might also be the last best hope for Wonderfalls, the quirky, Toronto-lensed Fox dramedy that was canned after four airings earlier this month. Creator Todd Holland (Malcolm In The Middle) is reportedly pitching the series to The WB.

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ON THE BUBBLE

TV’s going to look a lot different next year, with the demise of Friends, Frasier, The Practice, Sex And The City and probably Everybody Loves Raymond.

A few other shows, such as Ed, Enterprise, Boston Public and The District, are probably toast this season, along with these other “on the bubble” rookies: Arrested Development (Fox), The Big House (ABC), Happy Family (NBC), I’m With Her (ABC), It’s All Relative (ABC), Line Of Fire (ABC), Married To The Kellys (ABC), My Big Fat Obnoxious Fiance (Fox), Steve Harvey’s Big Time (WB), Tru Calling (Fox), and Whoopi (NBC).