I'm not really sure how to take this. We absolutely have recordings of instruments. You can buy them as complete sets. You train on complete recordings, and then tell it how to use the sampled instruments to compose a song in the style of the trained data. Building something to make a waveform that looks like another waveform just seems like a very odd direction to take.

Yes, my standards are if it isn't at least as good as what's available now, what's the point.