So how many areas of the UK have you visited, and where in the UK/USA did you conduct this research to verify your findings? Do you really believe all of the people in Britain have only one accent, and that all American's have only one accent?
By the way...does he get one chip on his shoulder for his "Just sayin'" or are they reserved purely for me?
Obviously there are many variations of the British accent, just as there are many variations of an American accent. But the "stereotypical" (if you want to use that term) American accent is closer to the original English accent than the "stereotypical" British accent. I haven't done any research on this myself, but every linguist I've ever heard speak (or write) on the subject says that it is the case, and I assume that they have done the research themselves.
The reason why it is so makes sense. America, especially pre-20th century America, is very isolated from the rest of the world, so we have less influences over our language. Britain isn't isolated from other culture and languages the way America is/was, therefore the accent has changed far greater than America's. If movies and TV show's wanted to be accurate, they would have pre-Revolution American and British charactors speaking in a current day Midwestern American accent.