Twenty-two years ago, just before a pilot of The Cosby Show was screened at the New York "upfronts" (the annual dog and pony act that US television puts on for ad buyers), many critics were confidently declaring American television comedy to be dead. Pleasant procedural cop shows such as Magnum, P.I. and Simon & Simon dominated the ad-supported, lily-white airwaves, and there was not a single comedy in the top 40 programmes.

The argument was that character comedy, which had its roots in 1930s radio plays, simply was not relevant to a modern television audience. Though the network bosses hoped the jeremiahs were wrong - after all, the network with the number one comedy was always the number one network - then, as now, no one in power rushed to defend the genre. In fact, comedy has always been viewed as television's bright but embarrassing stepchild, skulking in the corner and licking the leftovers from other people's plates.

All that changed when, a few years later, The Cosby Show started to make money. Big money, especially for the independent production company that owned it. Bigger money than all the networks combined were pulling in from their in-house shows. Suddenly, everybody wanted in. The Cosby Show made so much money for its owners that in 1996 the networks successfully lobbied the Clinton administration to change the law to allow them to own 100% of the programmes they broadcast. Now, the vertically integrated big media companies commission 85% of their shows in-house, the independents have almost been driven out of business, and not a single comedy money-spinner has been developed for nearly a decade.

Still, we in the creative community live with the illusion of accomplishment. American writers churn out an average 200 comedy scripts a year (each paid, on average, $100,000) to get 50 produced pilots (average cost, $2 million each) to get (approximately) 10 new series (average cost, $20 million each) to, hopefully, get one new (fingers crossed) hit. As they say in Hollywood, we're talking real money here. Yet not since Will & Grace and That Seventies Show premiered within a few weeks of each other nearly nine years ago has anything even raised a pulse in American syndication markets. Sure, there's been the odd hit, or something off HBO, but, for the most part, network television comedy doesn't seem to be connecting with the audiences in that nice (kerching!) way anymore. So, apart from the colossal financial waste, what is going on?

First, reality television (thanks, Britain!) is cheap, and, though it doesn't repeat well, it consistently occupies at least a third of any schedule. In fact, the buys this year reflect a decrease not only in narrative comedy, but in scripted programming in general. It's just no fun owning this kind of stuff when DVD sales are flattening out, repeats are not delivering, and international buyers are not keen.

In addition, the networks have picked up quite a few spin-offs of existing dramas this year, thus cutting costs by doubling up on writing and production staff, and reducing the need for new ideas.

On top of all that, the smart money is betting there will be a Writers Guild of America strike in October, which is not funny for the networks, and for which they are preparing by arming themselves with increasing amounts of "reality".

Second, television is a middle-aged medium that has almost given up on providing scripted stuff for the kids, who have registered the lack of interest and gone elsewhere for their giggles. So the audience is not renewing itself. Third, even older viewers know how to use their DVD recorders, so why would anyone pay attention to network schedules anyway?

The networks' thinking goes like this. "Things aren't looking good for us. We need to find a way to make more money, pronto. Those scripted comedies are costing too much to produce. No one agrees on what's funny anyway - even our cool niche cable channels can't seem to come up with any winners. The syndication market sucks, we're spending our own money on you, dammit, and we've tried and tried but nothing's worked, and we're frustrated after eight years of this shit, and wipe those crumbs off your chin you stupid idiot!"

So, all you Brit comedy writers, the next time you whinge about how the BBC, ITV, Channel 4 or any other UK network deals with your scripts - how they mis-schedule them, how they never get back to you, how they give you inscrutable notes when they finally do - just remember that you may go through some rough patches, but you are also loved, appreciated, and sometimes even well paid.

· Caryn Mandabach produced The Cosby Show and Roseanne. She has a first-look deal with the BBC