Comedy as Tragedy

Why are Britcoms acceptable PBS fare? Have you seen "Keeping up Appearances"? It is Married with Children/Roseanne, shows that would never have been broadcast on PBS. I realize that our Britcoms are several years old by the time they get here, but what is it about the British accent that makes stale sitcom idiocy ("Are you Being Served?", I am looking at you) somehow more intelligent or prestigious (the sterotype about itself on which PBS survives)? I feel like often we are being fed the slops that the BBC no longer wants and saying "Please sir, may I have some more?".

Why? Can't we at least get decent BBC shows like "The Office"? And can we stop telling ourselves that 70's era BBC is the height of network comedy?
Thank you. Ranting complete.