To you? as an American?
Some may be trying to emulate a new world style (e.g. Rolling Stones).
It also depends of the style of music you’re talking about. Singers with strong British accents are less likely to be heard in the US. Just like US country music is basically unheard in the UK.
In many other cases, you might notice the British accent less (though it is still there), because the way people sing draws out their syllables a lot more, and one of the distinctive characteristics of the stereotypical British accent is its clipped brevity.
I think this is the most important factor…....
Also, it may have been way more noticeable before the “British Invasion” of the USA….
The ‘traditional’ US popular music (country), as well as most black music since the 60s sounds incredibly American – by accent – to me. Aside from that, many indie-style bands have been emulating the British aesthetic…. for years now.
I was surprised that The Killers were American…
but it makes sense, the UK is a MASSIVE music market… pretty much second prize after the US. The Killers have sold 6m albums in the US (pop 300m) and 5m in the UK (pop 60m)
With the exception of US ‘country’ music, the two markets are basically in synergy.
There has been an unparalleled degree of cross-pollination between British and American culture… like nothing else in the history of humanity…. There are distinctly American styles, and distinctly British styles, but there is also a fairly broad middle, where British and American singers both appeal to an ideal moulded over decades by the two consumer markets and also legends from both sides of the pond.
I leave you with some Blur
and some more =P