This is a direct quote taken from the Prince interview with Guitar World.
GW: With digital editing, it is now possible to create a situation where you could jam with any artist from the past. Would you ever consider doing something like that?
(Prince) O(+> : Certainly not. That’s the most demonic thing imaginable. Everything is as it is, and it should be. If I was meant to jam with Duke Ellington, we would have lived in the same age. That whole virtual reality thing... it really is demonic. And I am not a demon. Also, what they did with that Beatles song ["Free As a Bird"], manipulating John Lennon’s voice to have him singing from across the grave... that’ll never happen to me. To prevent that kind of thing from happening is another reason why I want artistic control.
Was Justin aware of this interview? Was this the reason for the change? BUT isn't the "sheet screen" kind of the same thing? As a Prince fan I must admit this is interesting. I'm going to keep looking into this. Stay tuned.
Hit this link for the full interview in Guitar World.