Aisha Hassan & Dan Kopf, writing for QZ:
The median length of Billboard Hot 100 songs dropped from over four minutes in 2000 to around three and a half minutes in 2018. Over the last few years, the number of songs in the Hot 100 under two and a half minutes skyrocketed from just around 1% of songs in 2015 to over 6% in 2018.
So what happened? Streaming appears to be a big part of the story. In 2015, streaming overtook digital downloads as the music industry’s biggest source of revenue in the US. And streaming has dominated ever since: In 2015, it accounted for 34.3% of revenue, and that’s increased to 75% in 2018. In the process, many artists have adapted to the way their music is consumed. More streams make more money, but even then it’s not a lot, which is why volume is so crucial.