Pop music (a term that originally derives from an abbreviation of "popular") is a genre of popular music which originated in its modern form in the 1950s, deriving from rock and roll. The terms popular music and pop music are often used interchangeably, even though the former is a description of music which is popular (and can include any style), whilst the latter is a specific genre containing qualities of mass appeal.
Mass production can often lead to poorer quality. Perhaps this is what happened with "pop music".
With that said, I have liked many songs that I've heard over the years, and I like many songs created before 1955 also.
Accept the past. Live for the present. Look forward to the future. Robot Fusion
"As our island of knowledge grows, so does the shore of our ignorance." John Wheeler
"[A] scientist looking at nonscientific problems is just as dumb as the next guy." Richard Feynman
"[P]etabytes of  data is not the same thing as understanding emergent mechanisms and structures." Jim Crutchfield