It is a curiously British thing to take a sledgehammer to your own success, but that is what is regularly done - and it is, of course, partly the fault of John Cleese.
In the good old days, when your sitcom was commissioned, you milked it for all it was worth - and no-one thought worse of you for so doing. They still do that in the USA. And it's fair enough. If you manage the Herculean task of not only getting your show on air, but getting it recommissioned, and then re-recommissioned, why on earth stop? The odds are that it won't happen again. Note that even the greatest scriptwriters have penned plenty of failures that had all the ingredients but never quite worked. The cake didn't rise. The magic dust blew away. You get idea.
Fawlty Towers, a show that was largely ignored and disliked at first, may have been one at the vanguard of this habit of stopping just when they'd cracked it. Naturally John Cleese and Connie Booth were perfectly at liberty to do whatever they liked with the masterful comedy, and many people admire their restraint in stopping when the show was still good.
But why wouldn't three more series have been good? Episode 13-30 of Fawtly Towers could have explored any number of subjects and themes. Let's face it - they had the audience in the palm of their hand. The characters could all have been sellotaped to a giant bomb and it still would have got huge laughs. Once the engine of a sitcom is running, it'll serve you well for many years to come (unlike the engine out my VW Golf which I was forced to sell last year. That's for another blog - and doesn't even have a humourous story that's usable for a sitcom episode one day).
The Young Ones cut things short early and killed off everyone. Blackadder only gave us four series before hanging up their cod-pieces. Ricky Gervais 'got out at the top' in his own words on both The Office and Extras. Likewise, Corden and Jones seem unwilling to write more episodes of Gavin and Stacey - a lovely, heartwarming comedy with characters I'm only just getting to know. Why stop? I'm sure they have their reasons. New projects often seem more exciting than old ones. Understandable.
But what are British writers in general worried about? Is it concerns about a backlash? It is worries about people thinking you're cashing in your success? The British, after all, are very suspicious of success and wealth.
In America, they celebrate success. This doesn't make American's better people, by any means. Nor does it make them worse - although it does at least mean they can be happy for other people, and therefore not feel the need to constantly self-deprecate, that charming quaint British custom. This, perhaps, explains why their sitcom hits run and run and run. Friends, Frasier, Seinfeld and dozens of shows we've never even heard of make 24 episodes or so at a time. A show could run for ten years. I, for one, am glad there a nearly 200 episodes of Seinfeld. The last series was particularly funny and inventive (except for the finale - eek).
Of course, getting a show to run more than even 12 episodes is really hard work. But is that the reason Brits don't want to continue once they've done 12 or 18? Who knows? All I do know is that getting a new series up and running, and then to have it taken to the nations hearts, is even more hard work than keeping an old show fresh. I'm heartened that the writers of Peep Show keep bashing on. The fans love it. They cast and writers enjoy making it. Why stop success?