Rock music did not exist until the release of Meet the Beatles in January 1964. From that time until 1970, the Beatles were simultaneously the most artistically gifted and commercially successful rock artists on the planet. Then they broke up. And at that point, rock split into two opposing ideologies; there were now two kinds of music. The prime directive of the first kind of rock was to be meaningful and important; the prime directive of the second was to entertain people and move product. The first category comprises elements (Springsteen, punk rock, early U2, Chris Carrabba, etc.) that followed a template built by Dylan in the 1960’s. The second category comprises things (Elton John, Disco, everything the Stones did post-Some Girls, Michael Jackson et. al.) that followed the path KISS chose when they formed in 1973. Their era includes 2 exceptions, which are Led Zepplin and Prince; everything else fits into either category A or B. And that is the entire history of rock music.