Yeah... people loved Avril before too. And im pretty sure The Beatles, Spice Girls and Adele (ALL of them British) would be even more successful if they were american. And is THAT what I'm talking about, I'm not saying they CANT have success ..Im saying that the vision "america for american" reamains. Wait a few years till you see what will happen to Bieber.
Another thing happens in America faster than any other country too: COPIES. If something is a success and foreign lets do an "american" version of it. People will deny these questions or avoid it, but it is very easy to find scientific research about these things.