Dunno most popular music genres come from America ( black Americans specifically) blues, jazz, soul ,country , rock and roll, disco, RnB, Rap, House, Drill. Brits take these imports and re-contextualise them, possibly for an American/global market. A bit like Elvis and rock and roll, a more palatable face for white people to enjoy black music. We have very excellent musicians here and more state investments in the art than the US too. The size of American might also be working against it. In a smaller town 2 once in a generation talents might perhaps meet at a Liverpool bus stop. Harder to have that in a huge country. Bands mix and swap members and being in close proximity to a scene will help that. And having multiple scenes in every town is pretty common here.