Most people stopped buying records. CD shipments slumped by 75 % from 2015 to 2020 in the U.S for example. And streaming does not favour Maiden's type of music in chart calculations. It takes a long time to listen through Senjutsu, but it's still just counted as 10 streams. Drake can achieve that number a lot easier.So what was the difference between Book of Souls and Senjutsu then?