With the advent of electronic instruments, specifically synthesizers, will people still need to play the actual instruments? Rather than spending years mastering an instrument, could someone who has mastered the synthesizer be able to simulate playing that instrument, and also simulate playing other instruments...or many instruments at the same time.
Could this lead to a future where when you attend a symphony it's actually just a small number of people playing synthesizers that simulate every instrument in the orchestra. Each individual simulates a class of instrument (woodwinds, brass, stringed, percussion, and so on).
Added to that is the more recent introduction of vocaloids. They still need a bit of work, as shown by this:
However, as with all things involving computers, they will improve. Could this lead to a future where one person, with one computer and the appropriate programs, could create an entire performance. They have already managed to create, via holograms, an entire performance as shown by the following:
...and also bring cartoon characters to the real stage as shown the following: