The tests must reveal what is easily deduced: most, nearly all people do not enjoy much variety. They want to think they do, but their actions prove otherwise.
This sucks for you and me but is Spotify giving the masses what they actually enjoy.
Many years ago my most listened song (on ripped CDs in iTunes) had a few thousand plays because I turned off my headphones (analogue wireless!) while I had a track on repeat, only actually planning to listen to it a second time, and went on holiday for a week.
This sucks for you and me but is Spotify giving the masses what they actually enjoy.