Here's the thing. You want to write the first full draft to the best of your ability and with everything you have. But there comes a point when it's time to call it.
There's a point at which you bring in an editor, and it's the point at which you call the first draft done.
Because that editor? She's going to help you see it fresh. She's going to tell you where more is needed, and she'll give you new ideas and places you can possibly implement them.
In short, she'll help catalyze your creative juices for the next draft of your book — which is just what you need when you've written your well dry on the first draft.
The point here is this, dear writer. You don't have to get to the finish line by yourself. Your book doesn't have to be print-worthy before you hand it off to an editor. That's her job in working with you, after all — to get it to that print-worthy place. You just have to know when to call that first draft done. You have to be willing to call it.