What happened to "leave 'em wanting more"?

It was announced today that CBS (and therefore presumably CTV eventually) has renewed The Big Bang Theory for another three years. The fact that it's a three year renewal is apparently particularly remarkable, the norm being one year renewals with two year renewals in exceptional cases.

I like The Big Bang Theory. It may be my favourite show on television at the moment (since CBC, Vision and PBS are all too inept to carry Rev). Even so, I'm not convinced this is a good idea.

The show has shown a remarkable adaptability, incorporating new regular characters like Bernadette and Amy without sacrificing the essential chemistry. (Indeed, the addition of Bernadette allowed the Howard character to move beyond one dimensional creepiness.) Many of the recent episodes and story arcs have been quite good, especially those surrounding the slow evolution of the Amy - Sheldon relationship and Penny's big gamble in quitting her job to focus on her acting career.

But there have also been lame episodes where it seemed like Chuck Lorre and Bill Prady have been dialing it in. Far and away the worst was the show where the Leonard, Sheldon and Howard are encouraging young girls to pursue careers in the hard sciences while Bernadette, Amy and Penny get princess makeovers at Disneyland. The premise was idiotic. Why would you task an all male team of socially awkward scientists to come up with a plan to make science appealing to adolescent and preadolescent girls? The poor premise was made even worse by the condescending depiction of the two characters who are actual scientists (one of whom is a scientist in real life). And was anyone else creeped out by the contention that seeing your wife or girlfriend decked out as a Disney princess was supposed to be a powerful aphrodisiac?

It is easy for a series to go on too long. The fifth and sixth seasons of The West Wing were getting so tedious that it led to the creation of "Please Cancel Our Show" fansites. It wasn't until the story arc for the final season that the show recovered its mojo.

I fear the same thing may happen to The Big Bang Theory. Prior to today's announcement, I'd speculated to several friends that we were in the penultimate season. I predicted that Leonard and Penny would get engaged in the season finale and that next year's story arc would be the preparations for a show finale (double?) wedding.

Well, so much for that.

I don't see how the central Penny - Leonard tension can be maintained for another three years. The focus could shift even more to Amy - Sheldon developments, but even that would have a limited shelf life. I fear that Lorre, Prady, Warner Brothers and CBS may have pushed a great series beyond sustainability with this three year extension.

I hope I'm proved wrong, but I fear it will end with a Big Whimper.