The start of the 2009-10 TV season should be a time of celebration in Hollywood. When the Premiere Week spigots open up, nearly 100 hours of Hollywood production will plead to be seen. Plots will get rescued from hanging cliffs, series cast members will jockey to become the latest career made -- or remade. Cinematic commercials with hot new wheels showcased on coastal highways and desert mesas will litter the prime-time landscape.

But instead of celebrating, Hollywood creative types are flinging themselves on their sofas and chewing the cushions in an agony of grief over the coming season's Big Broadcast TV Experiment.

They've survived experiments of the past -- those that have stayed (reality TV) and those that have gone (prime-time quiz shows). But no experiment has ever been such an outstanding blot on the public's best interest as NBC's decision to push out all of its drama series time slots at 9 p.m. Monday through Friday for its new Jay Leno-hosted comedy/talk/variety series.

That's five drama series time slots gone. (OK, maybe three drama series and a couple of "Datelines.") Anyway, if you then add in NBC's two-hour fat-farm competition series "Biggest Loser" on Tuesdays, the network's "NBC Rerun Theatre" on Saturdays and its NFL football package Sundays, what you've got is NBC -- once the strutting peacock of scripted programming -- airing a mere eight hours of scripted series each week in the coming TV season, out of prime time's 22 hours.

Eight hours is the same amount of prime time that CW is devoting to scripted programming in the fall. That's remarkable because CW does not even program the 9 p.m. hour at all during the week, nor does it program Saturday or Sunday nights. CW gave Sunday night back to its local stations this coming season.

Meanwhile, CBS, the country's most popular TV network, will air twice as much scripted fare as NBC: a total of 16 hours per week in the fall.

So why is NBC forsaking scripted series at 9 on weeknights? It's all part of NBC's plan to continue the rewriting of the Broadcast TV Playbook.

The decades-old Broadcast TV Playbook is predicated on two basic principles:

• It's all about ratings.

• You can spend your way to a hit.

Relying on the playbook as their bible, broadcast execs have shelled out tens of millions of dollars to put as few as five and as many as 15 new series on their prime-time slates each fall, in hopes that one series, or maybe two, really clicks with, say, 20 million viewers in nice round figures.

"Cowabunga!" cries Madison Avenue, whose advertising suits begin to cough up crazy amounts of money to buy 30 seconds of ad time for their clients in the new hit series.

"Yowza!" shout honchos at cable networks and local TV stations, who start paying Insane Money for the rerun rights.

"Ooh la la!" rave overseas TV network honchos, who fork over even more Stupid Money for the right to dub the shows into their native tongues.

"Whoopee!" scream rabid fans, who fork over Silly Money for the complete first-season DVD boxed set, for which they may never cut the shrink-wrap.

All those other new series -- the ones that did not snare enough viewers to survive -- get tossed in the Collateral Damage trash bin. Then the whole thing starts all over again, resetting the game for next TV season.

NBC is now playing a different game, with new rules. That game is called Programming to Margins. NBC suits think they can win by slashing costs to rack up points with shareholders and thus declare a new form of victory in which you can win even if you haven't had a bona fide hit in years.

NBC suits know Leno's new comedy show won't attract as many viewers as the scripted dramas the other networks have scheduled at 9 p.m. weekdays: "CSI: Miami," "Private Practice," "The Mentalist," etc. They concede that this means advertisers will not pay as much for ad time on Leno's show as they will for ad time in those scripted series. The execs believe they have guaranteed their own success if only because Leno's show will cost so much less to produce. Leno recently bragged to a gathering of reporters that he can make a whole week's worth of "The Jay Leno Show" for the price of one episode of "CSI: Miami."

NBC's bold programming move has shaken drama-series writers, directors and actors right down to their very sense of entitlement. TV drama series writers recently spoke -- to an even larger gathering of reporters -- about Leno's new show. Among the yeastier comments, Peter Tolan -- the well-known TV series writer whose credits include "Rescue Me," "The Larry Sanders Show" and "Murphy Brown" -- called the Leno thing "craven."

"You can't stack (Leno) up against 'Hill Street Blues,' " Tolan insisted. Tolan would have a point, were "Hill Street Blues" still on NBC's schedule. Sadly, it is not. Instead, for the past few years the network has been trying to foist 9 p.m. dramas like "LAX," "Lipstick Jungle" and "My Own Worst Enemy" on an unsuspecting public.

But for this coming season, NBC has decided that if it's going to give us a good laugh at 9, it should at least be on purpose.