Quite prescient about the replacing of musicians by electronics, but completely missed the fact that sound would be recordable, with the subsequent exponential growth in the range of titles available to anyone.
That's actually a common theme I've found in AI--- people underestimate how much of the way to automated generation you get by just selecting from a large library of canned things. Given a catalogue of every jazz album every recorded, and a good way to pick the one you wanted to listen to, for most listeners, you've already "solved" the problem of automatically generating jazz tunes. The only people it wouldn't solve the problem for are those who are so familiar with the entire existing repertoire that they genuinely need a new one.