you're confusing performance with the underlying intellectual property (e.g., the published song)

It's the same fungibility argument though. The market for sheet music for Willie Nelson's catalog isn't affected by the availability of other music, is it? If I want to play On the Road Again, there's only one IP owner for that.

Depends if you want _that_ music that you remember, or are looking for _some_ music that you'll like though. Once you're going into it with no prior values, price popularity and expectation of interest will dominate your choices, at which point computer generated options will be totally viable.

oh got it, good point. yeah there is low substitute effect