they're exactly the same customer, the difference between those two is actually negligible, ignoring the new middle man and VC funded tech company in the way.

Both someone who streams, and someone who buys the CD are paying the same amount of money, the difference is that the person streaming gets a MUCH broader wealth of music, and much more music to listen to, for the same amount of money. Which means, on average, you would expect someone who uses streaming to pay less than someone who buys physical media.