As I see it, the artistic process is different from other processes for those who are not making a living on it and don't expect to. Because quality is more important than quantity, finishing something is only one part of the larger process which has several other stages or components. These stages or components have to be decisively addressed before something can be finished; things will remain unfinished until at least a tentative conclusion can be met about how best to proceed with the other stages or components of the process. It's quite often better to contemplate a creative problem as long as necessary for an answer to become apparent than to rush or skip ahead simply in order to get some sense of closure or completion on a work that it less than it might have been with a little more patience and extended consideration.

In my own case, I mostly write string quartet music. I work on many pieces a little bit at a time in rotation. If I'm having a block with one of them, it's often present in several others, so it will tend to be worth thinking about rather thoroughly from many angles. If I find a solution, it will often result in progress on several pieces. I consider a score to be 'done' when I no longer see any reason to add or change any pitches or durations. Usually, though, I'll not complete notating tempi, dynamics or articulations until some time later. At that point, I MAY make pitch and/or duration revisions.

I understand that stone sculptors mostly can't work this way. Their studios would either fill up with vaguely misshaped marble blocks or they would gradually 'revise' buddha-like figures down into skeletons. Your medium constrains your process, but if your medium is text (or music notation), there's very little physical material involved, so there's not necessarily any reason other than time, itself, not to keep reworking things until they're as good as they can get.

See how many books Herman Melville wrote and how many books Danielle Steele has written. Which books would you rather have attributed to you?
It's easy to assume that Steele thinks more about quantity and deadlines than did Melville, but we don't really know what their pocesses are.

If you at least have a draft and you don't NEED to sell it to anyone, why not take your time and get it right? Steele may have made a pile of money in the 80's and 90's, but in 100 years, most people will probably prefer to read Moby Dick repeatedly, rather than to read any number of Steele's books. That's what a 'classic' is.

Stephen King is an intersting case. He just writes and writes and writes. Some good. Some not so good. I'll bet you anything, though, that he starts A LOT more stories than he finishes every year.