The Beatles

For better or worse, they have marked the history of Pop/Rock, influencing dozens of artists who came after and became essential in their own right. There are those who contest their influence on modern music or claim that they "didn't invent anything." If you think this way, know that no one has ever invented anything from scratch. Mozart didn't invent classical music just as Kraftwerk didn't invent electronics, and Elvis didn't invent Rock'n'roll. They were certainly famous and commercial, and it's precisely this that made them more influential than many others. Shall we also deny that other incredibly important artists like Pink Floyd, The Who, Rolling Stones, or Led Zeppelin were famous and commercial at the time? This shouldn't diminish their significance. The concept underlying pop is rather simple after all: those who can afford significant visibility exert a substantial influence, while those who, for various reasons, cannot escape anonymity wield less influence.