This is Best Artists/Bands not best album release. Collective Artists Release's. Some bands did much better in previous or later decades. Only one album results in lower on chart.All 80's releases with consistent high reviews charts higher. Multi site algorithms. Surprising results.
http://www.ranker.com/list/best-hard-rock-artists-of-the-80-and-_39_s/scarcrifice,
Black Sabbath
Dio
Iron Maiden
Metallica
Motörhead
Ozzy Osbourne
Rush
Slayer
Triumph
Whitesnake