From a revenue perspective, success is much less about an artist capitalizing on their existing audience size elsewhere, and more about an artist engaging consistently over a long period of time.
And with the perfect confluence of 10X more users, 5X more time spent online, and the ability to connect behaviours, engagement & publishing sentiment across multiple devices – this gave Google & Facebook each an immense treasure trove of data on each of its users.
The fact that Amazon just drastically reduced its affiliate fees is perfect evidence of how little negotiating power these individual sites have in this value chain, despite their collective importance.