What country has birthed greater music? america or the uk?   stance: america:
I am an Englishman who predominantly enjoys English music. Yet I would argue that America has birthed greater music.
The whole bedrock of modern popular music is founded upon Blues and Jazz which as we all know originated in the US.
Without Blues and Jazz there would be no Beatles, Rolling Stones or any other major British band pre 1977.
Don't forget there's also Hip-hop and Punk. Both original American art-forms which have had a major influence upon the UK music scene since the late seventies and early eighties.
In terms of popular music the US leads where the UK follows and adapts.