Anyone's productivity can be measured, or at least what's left of that productivity after measuring. You may know nothing about how musicians make music, but you can measure superficial traits, such as the number of distinct notes used per minute of music, the feedback score from a committee you hired, the lead time to deliver a musical unit, and so on.
These people want to optimize making money. If you compare technical musical ability against musician income, I suspect you'll find a surprisingly weak relationship.
