Why is pop music such a popular genre of music? what makes it so popular?

There are 2 main reasons that pop music is so, well, popular.

1. "The Shazam Effect": When music identifying service Shazam launched in 2002, it was intended to help the everyday music listener discover new music. But by 2014, the app had become more than just an identification tool; it was the music industry's newest weapon to discover up-and-coming artists. "The Shazam Effect," as it was recently named, uses the data Shazam collects from listeners to determine what songs are catching on, providing the music industry with a useful set of metrics. Sonny using "The Shazam Effect", music is more similar, causing you to like it more, regardless of how good the song actually is.

2. Studies suggests that the more we hear a song, the more we like it. Our brain's reward center is more active while listening to songs we've already heard, so the more we hear Ed Sheeran's new tracks from "Divide" on the radio, the more we tend to consider it a good song. It's kinda like Stockholm syndrome in a way.