As the linked video here illustrates, simulated neural nets, via blindingly fast trial and error, can create the connection patterns that lead to what we see as creative output; whether that output is the ability to play chess, or construct music that is as similarly pleasing as what we create. What you have to remember here is that such engines will never have the connection to the feelings that made those music patterns desirable in the first place. Said another way, if they had been left to themselves without samples to start with they would have been unable to create anything but random patterns. Which is to say that we have a very unique type of connection to meaning space. Such synthetic neural systems can mimic the pattern recognition strategies we've developed, but they would never have been able to create what made them resonate with the feelings that these patterns have had for us from scratch.
You need to keep this in mind as we allow the current economic pressures of competition, competitive edge, and zero sum games of power, and the application of power (whether to preserve markets, or the resources to make and dominate markets) to delude us into thinking that such machines are in our interests to keep developing and improving. Certainly these machines will be able to eventually operate these mechanistic systems better than we do, but the motivations as to why, and for what ongoing purpose, will have little connection what we have as a meaningful or desirable. Especially if what you think of as meaningful is the balance of Mind and Rationality, with that which transcends objectified rationality (which is precisely what the feeling of powerful music is a part of). The kind of balance that would encourage thoughtful, loving structure (where we cherish both reasoned inquiry, and what it means to embrace each other, in all of the various ways, that express care, love and empathy).
The problem here is two fold: Not only is our current economic operating system not conducive to thoughtful loving structure, the final step in electrifying that system would make us, or anything related to what human interaction truly requires, irrelevant. Why have labor derived mass production for mass consumption when the machines can make things better than we can, but for which they would have no need to consume in such quantities. How could it not but leave the machines with little but one option to fall back on: self maintenance based on doing it better, and finding out how to do it better; a context in which I would think would put most everything biological into very specific niche categories of usefulness, of which irrational, chemically inefficient, vertically symmetrical bipeds, would not have much to recommend them for.
You need only to think about this a short time to see the pathetic irony here. The same insane thirst for power, which has kept us using this inhuman economic operating system, is unavoidably attached to developing the ultimate competitive edge machines, not realizing that we are a significant part of what will be in competition here. A competition we are doomed to fail at. Change the nature of how you operate, however, and you take away the need for such insane competition altogether. If we start striving to be better connected to each other, we will make learning about, and understanding the entirety, so much easier, and always within the scope of our type of sentient meaning space.
All of that job security musicians so enjoy is about to go right down the drain.