"What is the success metric for these playlist companies?" Extremely difficult to determine. And the 'taste-makers' in music are very hard to find, though the

"What is the success metric for these playlist companies?" Extremely difficult to determine. And the 'taste-makers' in music are very hard to find, though they should easily have access to the latest/hippest tracks. Design is one of the hardest things for a reason. If fashion truly were a commodity H&M etc. simply would not exist.