All of my stories begin with far more words than ever reach the reader. Most of my short stories were almost three times as long in their original draft. As the sculptor said modestly about his works, "It's easy to a produce a statue once you see the part of marble you need to remove."
To begin with, editing a first draft is easier than the writing of a story. At that nescient stage errors of haste become glaringly obvious, as does any material irrelevant to the story. Most misspelled words and grammar mistakes are hopefully taken care of automatically so are of no concern (except when you're writing SF of course.) Editing becomes increasingly harder with each succeeding draft as you struggle to clarify and improve the action while honing descriptive and expository sentences into razor-sharp clarity. This last effort (reaching for the perfect word/sequence) can become as tedious as picking fly scats from the pepper line and would appear being overly compulsive to any rational observer.
As a case in point, take the piece I just completed (on the fifth draft.) The opening paragraph was the most important scene in that it was supposed to grasp the readers attention, raise questions that impel them to continue, and create a sense of anticipation so that they immerse themselves in the story's progress. At the fourth revision my opening paragraph was 566 words long and, I thought, rather inelegant. After a full day (six hours) of struggle I had reduced the word count to a more precise 213 words with greater impact.
I did this with two key internal scenes as well and, on reflection, the third draft would have been acceptable ( to the right editor, of course) and I question whether I was needlessly embellishing the piece without actually improving it. This is a question that remains uppermost in my mind as I grind and polish each facet to get microscospic improvement to the work.
But then, that's just me.