Dean Koontz, if I remember the spelling of his name correctly, writes popular horror fiction in the United States. Years ago he wrote that for every page of a book he gets published, he has written 9 drafts on average. In other words, every page is rewritten and rewritten and rewritten. He considers this part of the writing process.
Why would anyone rewrite that much? If the goal is a piece that catches the reader's attention, is consistently interesting, flows smoothly, and is intellectually and emotionally powerful, but the writer has to rewrite and rewrite to get the piece up to that standard, he just puts in the time and energy and does it.
I remember that in high school, rewriting a book report just to make it legible seemed a nuisance to me. But reading this comment by Mr. Koontz changed my whole attitude about rewriting. Since then, I've always considered the rewriting process as equally important as my original ideas. And I don't complain, no matter how long it takes to rewrite a piece. I just keep working.