Because, if one is writing novels today, concentrating on the beauty of the prose is right up there with concentrating on your semi-colons, for wasted effort. ↗
I'm one of those writers who tends to be really good at making outlines and sticking to them. I'm very good at doing that, but I don't like it. It sort of takes a lot of the fun out. ↗
Write your story as it needs to be written. Write it honestly, and tell it as best you can. I'm not sure that there are any other rules. Not ones that matter. ↗