But an editor is there to edit your work, not write the book for you. Yes they can guide you, definitely advise you, but it's not their name going as the author so you have to have realistic expectations. I'm sure some editors will turn away work if it involves poor quality writing, sub-standard story construction etc deemed beyond economical repair; but there are some that won't. Exactly the same as any profession, there are 'professionals', and there are some 'not-so-professional'.
So, my point here is this: Yes it is of great value to have a working knowledge of social media, marketing and advertising, definitely. BUT, if your book/story is not of a good enough standard it won't sell anyway - what is the point of having a thousand follows on FB or twitter if you only have junk for sale - focus on the quality of your 'product' first and foremost, focus on the writing!
And on that note, I'm off to work on WiP 2 - an unknown story.