If the first six months of 2024 have proven anything, it’s that rock ‘n’ roll isn’t just alive and well — it’s taken on plenty of different forms. The first half of the year has seen triumphant releases from stalwart headbangers like Judas Priest, Bruce Dickinson and Sebastian Bach, along with confident new albums from ’90s rock giants such as Pearl Jam, Green Day and the Black Crowes. Billy Joel returned to popular music after three decades away, and glam rock icon Ian Hunter showed he’s still got gas left in the tank. Meanwhile, Slash paid long-overdue tribute to the blues with a star-studde…