Hi Casey ~
Even though sometimes editing suggestions can be worded as though they sound mandatory for the piece to be successful, I think that typically there's an implicit ~ if not stated, though likely not each time ~ understanding between the creator and the 'editor' [volunteer or paid]. In other words, a "take it or leave it" attitude. Sometimes, the original writer [or creator] can struggle with trying to get something right... or simply not notice that something could be and would work better if it was slightly ~ or more majorly ~ rearranged to make it smoother [or whatever]. It's still the ultimate choice of the creator to use the suggestion[s] or ignore it[them].
There are writers who rely on their editors to clean up their pieces; yet, the piece in question wouldn't exist were it not for the one who conceived the idea and 'did' it. I don't feel it becomes a collaboration at that point. The input needs to be more substantive for that to happen... and really is a matter of exchange
throughout the process of creation.
It's more pure if the original artist does their own editing, of course; yet, input from others doesn't corrupt the process or validity of the work. An analogy that is a bit hyperbolic, but still might work with that idea is your [or a woman] getting dressed up for an important event. From the point of hearing about it, you start thinking about what you want to wear. You may shop extensively to find exactly the right outfit [which may involve a variety of components, which have also been selected by you]... or you may have it made by a seamstress for the occasion [either through an existing pattern that you've managed to locate, or through description to the seamstress]... then, the day arrives and, perhaps, you've had your hair cut/done... you've properly groomed yourself... you've dressed yourself... and off you go. On your way out the door or upon your arrival, someone sees a piece of lint that is distracting to the whole picture of 'you' and removes it. Compliments such as "Look at you! You're a work of art!" [taking that idea to extreme, for this purpose here] ~ or "You're the picture of beauty!" In accepting that compliment, you wouldn't [or wouldn't even consider it relevant] to point to the one who removed the piece of lint and say, "Thanks to that person, I am!" or "I was until that person got involved." It's not really been a shared effort of creation; yet, that piece of lint certainly compromised the picture as a whole. Or, it may have been an upturned collar; a skewed necktie; a slip showing [in the days that women wore slips

]; or a pantscuff caught upwards on a shoe. They're 'only' details; yet, ones that interfere with the observer's appreciating or becoming 'lost' in the overall impact [and/or beauty] of the original creation. I know that true beauty reportedly requires at least one note of imperfection, and whenever I've heard that, I've thought of a person's physical beauty and the many things that could be considerd imperfections. Rather than being 'qualifying' ones, however, the ones I've noted are 'interfering' ones.
It seems that I've heard that theory apply to a person's physical presentation [such as being dressed for an occasion], as well, though... so, it's possible my whole theory could just crumble

; however, I do feel that the specific examples I've used make it hold up, in so far as I've taken it, anyway.
Some people rely heavily on their editors... yet, even so do not take all the suggestions and will argue them out tooth-and-nail... and, whichever way it ends up going, the original process of creation is presumed to have remained intact.
I'd planned to say more, but just realized I'm 10 minutes LATE for an appt.!!
Okay. I can continue with even more details now [in addition to some I've added above]. I was a copy editor for a small newspaper for awhile... and neither I nor any of those who submitted their pieces considered my editing as an interference with their creativity. When I did some theatre reviews for another small newspaper [in another state], my pieces were looked over by a copy editor, with some being edited more than others. If the changes that were made weren't sufficient to affect the 'authorship' [being written by me], my name remained at the top in the 'byline' position. If the changes were more sweeping [this happened only once], my name was placed at the end of it, since I was still an integral part of the process... but the changes were just too many to really consider it as being wholly mine.
~ Lizzy