In 1977, the great computer scientist Donald Knuth published a paper called The Complexity of Songs, which is basically one long joke about the repetitive lyrics of newfangled music (example quote: “the advent of modern drugs has led to demands for still less memory, and the ultimate improvement of Theorem 1 has consequently just been announced”).
Check the analysis of the repetitiveness of a dataset of 15,000 songs that charted on the Billboard Hot 100 between 1958 and 2017 here.