Re: Software is not a creative work?
> instead of obsessing about lines of code, many of which are probably indistinguishable from lines used in thousands of other applications across scores of different domains.
Instead of obsessing about individual notes, many of which are probably indistinguishable from notes used in thousands of other scores across lots of different styles of music.
Instead of obsessing about groups of letters[1], many of which are probably indistinguishable from words used in thousands of other books across scores of different genres.
> visual design, interface design, component design.
> But it's the design that's by far the more creative aspect
Yikes, this is starting to sound like an argument from a "creative" who hasn't had the enjoyment of coding something new :-( But putting aside such derogatory remarks (tut tut Corner, Old boy):
Copyright only covers the *expression* of an idea/design/... and even by your own argument, that is the code (there are other ways to express the idea/... - you may have drawn your UI out on paper and written in the Pantones - and that is also copyrightable; but the code is the expression that is actually *useful* and worth disseminating).
Depending upon your location, you may be able to get a design patent on, well, the design; you may also be able to trademark some of it (e.g. a particular shade of purple used in a specific context - a list of applicable contexts is available from your local trademark office).
[1] yes, given the nlocs in something like Firefox, comparing lines of code to words in a novel or notes in a score is reasonable: certainly makes it easier to structure these comparisons!