Np Man's Sky does procedurally generated music and it took a band of professional musicians (65daysofstatic) and a musician/programmer with years of experience in procedurally generated music. So, I'd say it is kind of like graphics - it's coming, just not in our lifetime.
check out the references on the bottom of the tutorial i linked. there are already promising approaches, also ask youtube. a band of professional musicians for that doesn't sound real. there is a lot of stuff made by one man bands, not even professional musicians, who made great stuff. i developed my tool far beyond the tutorial, it understands music theory now. it just needs to sound more like dwarf fortress (and gotta be rewritten in c/c++).
No Man's Sky sounds like genetic algorithms/a trained AI. such is much more sophisticated and obfuscated and can hardly be controlled. i don't like the results of that approach. i am rather thinking about one or two key or plucked string instruments, randomly/procedural generated. a dev who knows what he is doing can make, given that he has enough coffee, something to start with on a single weekend.
and besides... yes, i am playing with randomly generated graphics as well

my giant nemesis beast project creates images, another smaller project generates maps for UT4. fully random. well, all blocky, shallow and dull yet since i need some <technical stuff> features which aren't supported yet but some people like it already. bonus: it is just one not all that complex blueprint and generates a new map in the blink of an eye, ingame, during gameplay.
in doubt, just look at the complexity of the generated stuff in DF. it is astonishing. and also shows that quite sophisticated results are already possible. we aren't as far away as you might think. DF creates a whole world. also we are talking about computer algorithms, not physics or fusion power plants. those are promised to be ready in twenty years. they just gotta fix that one tiny problem and it will all work. and they were promised to be available in twenty years about 50 years ago. but by solving that one tiny problem two other tiny problems popped up. computer science made significant progress, even in the past decade alone and in comparision it is lightning fast.
The game already has procedural music, uh, sort of. There's no specifics, just a description of the artform. The data structures regarding them aren't mapped out yet, either, so I can't do anything with them.
gave me an idea to make it easier and produce better results with less effort.
instead of *fully* random music, doing something like the Musical Dice Game developed by Mozart,
http://en.wikipedia.org/wiki/Musikalisches_W%C3%BCrfelspiel. Guess he counts as "Professional Musician"

Using hand crafted samples or very tight defined patterns/bars and put them together by some rules. like that quite complex patterns can be created which are granted to fit together and sound awesome. and larger chains of several patterns created that way can be refined and reused as well. these rules could be created out of the descriptions. Properly elaborated descriptions in natural language can be transformed into music. the algorithm just picks keywords and translates them to partially or fully predefined scores. "fast" means higher tempo at higher pitch and rather demisemiquavers, breves, maybe at lower pitch for slower parts, larger intervals and faster sections for playful, medium intervals for joyful, smaller intervals for thoughtful, and so on, as sophisticated as the developer likes.
Spore has professional music, too. It's not exactly mindblowing.
i guess what makes procedural music that awesome is that it doesn't sound like the stuff in the radio or played by orchestras. it is rather simplicity and to some degree that it is played like a child would play, free of all that complex thoughts and demands people have against musicians labeled as such. it is about making something nice, now and here, without remembering the cruel past and without worries about the scary future. it is not about politics, about culture just to some degree, it is not about knowing other songs, patterns or theories but a computer knows to play the instrument perfectly well. like a prodigy in kindergarten. at least that is a part of what i like about it.
uh... am i too gassy? too excited? like a kid? xD