Well, bear in mind that the population is much larger today than it was when Elvis was in his heyday, and people generally have more disposable income than they used to. So, even acts that were HUGE in the 40s, 50s and early 60s generally don’t have record sales that compare to those of more modern acts. A record that was #1 on the Billboard charts for a month in 1956 probably sold far fewer copies than a record that “only” made it to #10 in 1976.
So, it’s not necessarily surprising to learn that, say, the first LP by Boston sold WAY more copies than any album by Bing Crosby or or Frank Sinatra. Boston wasn’t necessarily as beloved in the 70s ans Bing and Frank were in the 40s, but they had the good fortune to make their first album at a time when there were a lot more people ready to spend money for albums.
The best-selling album of all time is “The Eagles’ Greatest Hits”- and one of the reasons it’s sold so well is that so many people have bought it in multiple formats! People who liked the Eagles in the 70s bought it on vinyl or 8-track, many later bought it on cassette (to play in their cars), and many eventually bought it on CD.
So, you see, longevity pays! “Frampton Comes Alive” may have sold 8 million copies when it came out, but nobody’s bought a copy since 1977! But an album like “Led Zeppelin IV” or Pink Floyd’s “Dark Side of the Moon” continues to sell steadily, year after year.
The following link will tell you the best selling albums of all time:
http://www.neosoul.com/riaa/
As you can see, the Beatles, the Eagles, Led Zeppelin, Bruce Springsteen, Pink Floyd, Garth Brooks, Whitney Houston and the Backstreet Boys all have multiple albums in the Top 25. One of those acts is probably the top selling recording act of all time. But since Led Zeppelin and Pink Floyd had VERY few hit singles to go with their smash albums, and Garth Brooks’ hits have been confined to the country charts, and the Backstreet Boys weren’t popular for very long, I’d say we can exclude them.
I’d be inclined to pick the Beatles, just because they had so many gold and platinum singles, in addition to all the albums they’ve sold.