IMO you have to take into account the times these albums were made. Metallica may not have invented metal but they changed it (one can argue if they changed it for better or worse). When Master of Puppets was released it was heavy metal and it remains a classic metal album in my mind. They’re later stuff, everything after and justice…goes pretty main stream. The video for One put them over in the mtv pop world and changed how Metallica was perceived, how they acted, and how they wrote music.