I imagine it's kind of important to remember the physical and cultural landscapes of the two countries. Many of the things that are valued in America are often seen as crass and vulgar in Britain, and just like if you compare British and American hiphop today you see a massive difference. Not only that but the physical landscape is different too; Britain doesn't have rampant gun culture, vast swathes of untouched wilderness, mythical highways etc.
And this totally comes out in the music. Sure bands have done covers of American songs but can you imagine a British band ever writing a song like Viva Las Vegas, New York, I've Been Everywhere? The Kinks sang Waterloo Sunset which touches feelings on a trainstation but singing about a city or a place in Britain with anything less than a deep dose of irony, melachony or sarcasm sounds embarrassing. It's why you don't have thousands of songs about London.
