Before the streaming era, only a purchase of a song or an album, as well as the radio plays would contribute towards the charts. With streaming, it is all about how many times a song or an album is played. Back in the 90s and 00s, you could play Thriller on CD or iTunes endlessly during the Halloween period, but it would have no impact on the charts. But now if you play Thriller endlessly during the Halloween week on spotify, it would have a big impact on the charts.
In some way, streaming platforms like spotify are great, as I believe that without the streaming platforms, legacy artists like Michael would not appear weekly on the charts. But as we are now approaching the Christmas period, we are going to see the music charts over the next two months flooded with overrated Christmas songs like All I Want For Christmas Is You, and that is something I am not a fan of.