It’s not really surprising that the US has more acts and therefore a higher probability that some of these acts will sell a lot when compared to the UK, who has a sixth of the population of the US. But, that isn’t what the OP is asking.
Besides, if you’re going to take the top ten bands by number of sales from that list, then the UK wins there: in the 200 million to 299 million records sold and the 100 million to 199 million records sold (i.e. the top two categories), the UK has seven artists listed compared to just 3 from the United States. Yet, that’s clearly absurd, as the list goes on to mention the likes of Backstreet Boys, Olivia Newton John and Barbara Streisand as selling a lot.
They have five times the population, though. Per capita, the UK wins ;).
My take on this is that post-1963 US and British rock/pop/etc. music is so intertwined that it seems a little arbitrary to separate them and ask which is better. But I’d agree that in the pre-60’s recording era, US popular music wins by a mile. Until the 60s British recording artists were mostly just copying certain American styles without adding a huge amount of their own, and other major styles were largely overlooked. There were some people making uniquely British popular music, of course, such as music hall-style artists like George Formby.
I’m not so sure about classical music - some people have mentioned Copland etc., but there have been some significant British composers in that time too.
Well I tried to be objective about this, so I riffled through a box of my old CDs. American acts outnumber British acts by about 2-1 in there. So I went with America.
But if we were talking about quality output per capita, it would be the British hands down.
No question about it. Almost everything I listen to is British, even though nationality has no role in my musical decisions. The Beatles, the Who, the Kinks, the Hollies, Led Zep, David Bowie, Roxy Music, Black Sabbath, Sweet, Judas Priest, Pink Floyd, Genesis, King Crimson, Jethro Tull, Gentle Giant, Van Der Graaf Generator, Queen, 10cc, Supertramp, Kate Bush and Sparks (who are the most Anglophile Californians of all time and hit it big only after relocating to the UK). If a national ban suddenly forbade all American music, I wouldn’t notice, although I recognice the role it had in creating most all the above acts. The Brits just did it so much better, took it so far beyond.