If you want to find real, great British comedy then the best I've found recently was the political comedy called The Thick Of It (see avatar). The reason I'm guessing it hasn't been picked up in the US is because there are a lot of references that don't make sense because of the different political systems / culture.
That said, it's still in my opinion probably the sharpest comedy writing I've seen in many years.
The was a film version called In The Loop you may have seen, but the BBC original series was much funnier.
Although I think you're probably right that we trade shit TV. That's because most people like shit TV, so why spend all that time and money writing new stuff, when we can just trade already proven shows and tweak them a little. Much like porting a winning campaign from Adwords to Bing I suppose.
