YouTube already hosts significant factories of programmatically generated music; just look for Creators with the 3-hour or 10-hour or livestreams. For YouTube Creators, and also for Photos editors (that's everyone with an unrestricted Workspaces account), they provide a menu of background music that is "royalty-free" and so you can attach it to a montage or your own videos, to avoid awkward silences, or set the mood to vaguely sorta what you were hoping for.

So it's an evolutionary step in my view, rather than a revolution.