There's a few other things to this. One is that the music that's still recognized today is the best music of the era, but recent songs are merely average. Some amount of music knowledge is handed down from parents, so while the article calls it the "golden era" of music, it could just be that millennials picked leaned whatever their parents listened to. I have a feeling that interest tails off over time, and the Lindy effect just extends the tail of song recognition. How many classical composers can you name? And they span how many centuries?