Here's a note I wrote on a forum to someone who said he's a great idea person, but his grammar sucks. I assume that he's tried to work on his grammar, but it's just one of those things that he can't "get."
If you're aspiring to be an editor, you'll have to be an expert on Grammar. But if you're wanting to write books and articles, that's what a writing team is all about. Whenever I write an article or a chapter, I read it over and over it, trying to perfect it. Then I give it to my wife, who's a fast reader and can give me big-picture ideas. Then I make corrections and give it to my mom, who's a stickler for grammar - she's the comma queen, agonizing over whether this or that comma is really necessary. If you're in a writer's group, that's where they come in handy.
For a book, I'll give the manuscript to many other people, besides my wife and mom, to critique. They keep finding errors - some of fact, some of grammar, some of consistency or logical development. These are not typically professional writers - just people who like to read. (They're typically glad to look it over, honored that I respect their opinion. I give them a free book after it's published, then ask if they'll give me a review on Amazon. Since they've already read the manuscript, I get reviews right after it comes out.)
By the time I give a book to a professional editor, she's having to look hard to find mistakes.
Sure, there are some writers who can do it all, then turn it in to an editor for final polishing. Steven King used to teach English on a college level, so he can do it that way. But many, many others think of it as a team approach. James Patterson, the most prolific, best-selling author of our time, will "write" 9 books this year. He's the idea person; then he gives it to a team member to flesh it out. George Lucas can't spell worth anything - but he's a great idea person and can tell a great story. Lloyd Braun hatched the idea of the TV series "Lost." He hired Abrams and Lindelof to do the writing. And they involve others in their writing sessions as well.
Do you involve others in your writing? In what way? How does it work for you?