This great article is an essential read for anybody that wants to know how the digital music ecosystem got into this state.
In summary, music streaming services were built on the principal of the long tail (i.e. driving many small sales from a massively wide catalogue) but the vast majority of music on there has never been listened to. In fact, 80% of total sales revenue comes from just 3% of the tracks. Algorithms compound this by steering listeners towards the same songs and artists over and over.
So songwriters struggling to get their royalties back to physical levels by producing a greater *quantity* of songs are chasing a non-existent revenue stream.
Read much more over at the 5Mag website.