True, but you have to take into consideration the time. Britney's debut album was released in 1998 when people were buying music on CD's or cassette tapes. Nowadays, people are streaming and/or buying their music on Spotify/Apple Music/Tidal etc. Nobody is really buying CD's anymore. Of course Britney's numbers are way better (I mean they would be anyways since it's been out for 20 years but still)