Thrash metal’s “Big Four” are still trudging on in 2016. Metallica should’ve played the Super Bowl and have a new album in the works. Slayer released Repentless last year and are content to keep going without Jeff Hanneman. Megadeth just dropped Dystopia. Completing the cycle is Anthrax, the black sheep of the group, whose 12th studio album, For All Kings, holds fast to the band’s signature melodic thrash style. My question: How relevant is any of it? Why should we care about new material from our favorite ’80s metal bands as they retread the same ground, as they repeat themselves years, decades after their prime? For All Kings — like Repentless and Dystopia and Death Magnetic — is a safe and agreeable slice of thrash, but it’s also robotic, formulaic, and dated.