I've been watching a bunch of musicians on Youtube lately. I've found it surprisingly familiar, despite my lack of any serious musical background. I think it's because of the way music so explicitly embraces the idea of technical creativity.
As an art, music is particularly technical. Unlike visual art, it never really had a representational phase; nobody comes up to a guitarist and says "hey, can you play a river?" But unlike other abstract arts, it has some pretty inflexible constraints; consider the experience of seeing a random noise painting vs hearing a random noise band.
All the depth of formalism and structure in music theory is an attempt to wrangle with the fact that making music – not good music, just anything recognisable as music – is surprisingly difficult. You can't just take what you think of and play it; you have to know the rules before you even start getting creative.
This, I think, is an essential truth of technical disciplines: you have to start with the rules. There's no point designing a bridge if you don't know civil engineering, even if you can get a civil engineer to look at it afterwards. The problem is that most shapes of bridges won't work, so the only feedback you'll get is "nope, not even close".
In this kind of low-density idea space, you need an approach that eliminates most of the options that won't work right at the start. Then, once you've narrowed things down, the remaining space is much denser and you have the freedom to explore a little.
For many technical people, just getting to that point is difficult enough that creativity, as in the voluntary search for extra complexity, is the last thing on the cards. I mean, I got the damn thing to work, isn't that enough? What? What colour should it be? I dunno, what colour does it need to be?
To be creative in such a constrained system, you have to internalise its rules to the point where they no longer seem like rules. That's how you get to just do what you think of: you stop thinking of so much stuff that won't work. In a sense, you mind moves from the low-density space to the high-density one when you internalise the filter.
And so this is what I think music gets particularly right: cursed with a low-density idea space, musicians learn theory sooner and more aggressively than most other artists. Their goal isn't to become amazing theoreticians, but to internalise enough theory that what they think of will usually work.
At that point, what's left is which workable option to pick: not a technical question, but a creative one.