The Beatles changed the charts forever. You can draw a line in the historical sands of popular culture at 1964. A lot of pop music that came after that point still sounds modern today. Almost all the pop music that came before that point sounds ancient.
I know it's true, because I make half my living playing in a rock 'n' roll cover band. Yeah, we play Elvis, Fats Domino, and a few more pre-Beatles acts, but when we examine the charts to come up with additional material, 1964 is the baseline.
Look at it another way: try to imagine a cover band in the '70s playing songs from the 1930s, or an act coming to my high school in 1986 and playing tunes from World War II to the kids. Ridiculous, right? Yet teenagers today still bop along to Beatles songs when we play to them.