True. Specifics are sometimes kinda implied. 
I mean, if you’re digging into your mix and you’re having trouble dialing in midrange clarity because of a lot of midrange frequency masking the solution to that may not be using extreme EQ, it may be going back to the arrangement and using more open chord voicings, especially if VI’s are involved and that can be easily adjusted. You can voice the equivalent of a minor 11th chord multiple ways so if it serves the song better tonally, open it up to leave some space.
That’s what i kinda meant by arrangement and tonal clashing, masking, problems, assuming musicians would figure out the rest, being musicians. it’s not a matter of experience or talent, more just a matter of using common sense to solve issues like… does this chord “really” have to be all in this particular octave? What will it sound like when all the lead and backing vox and guitars go down? Can i spread this out and make more room in the midrange? Stuff like that.
Not that I’m a good composer, I’m not. But I can hear the differences.
Anyway, that’s what really great “music producers” (people hired to produce) do, care for all that in the production stage, which makes the mixing stage easier.