AS youm said, USA have a much bigger market for rap, mainly because thats where it originated from. Probably about 40% more even people or this board are from the Uk, but to be honest it has only really been big in the U>k since Eminem spread his wings. I'm not saying rap was unheard of or no-one listened, just it became alot more mainstream.
I don't really see many BRitish rappers making worldwide status in the near future, but i hope they do someday because there is alot of wasted talent floating about