There is a spectrum, of sorts, of creativity. Writers are particularly aware of this, and the culture describes two ways of writing. One side is more unplanned, and the other side is more structured.
This is sometimes, and rather crudely, called "Pantsers and Plotters". I don't like "Pantser", because it reminds me of "Pantsing", which is yanking someone's pants down.
All things begin with ideas, even when that idea is an ineffable thing within the author. All exploration must lead to a finished product. A finished product must have will behind it. It cannot be a collection of notes stapled together.
Some people are more artist and others are more mechanic. Those who begin more artist are either lacking in skill or imbued with creativity. Those who begin more mechanic are either capable of skill or lacking creativity. Either way, they must end up as the same sort of person.
Perhaps an undiluted artist, a person who still ends up clearly an artist, must hand the book off to another for completion. Perhaps a mechanic, a person who can think in a more structured way, would be an excellent ghost writer. People can start off different and still end different, if they are working with or for others. But if working alone, a finished product of modest success must be approved by an architect.