What you are missing is that they are majority owned by the same record companies they are paying out 70% to. They even specifically structured the deals between Spotify and labels so that they pay labels in a way that allows labels not to credit artists for nearly 50% of all streams meaning the label gets to keep it.
Chokepoint capitalism by Cory Doctorow is a great book that goes into detail about how it works
What you are missing is that they are majority owned by the same record companies they are paying out 70% to. They even specifically structured the deals between Spotify and labels so that they pay labels in a way that allows labels not to credit artists for nearly 50% of all streams meaning the label gets to keep it.
Chokepoint capitalism by Cory Doctorow is a great book that goes into detail about how it works