I think this is overall pretty good advice, but I also think that the writing process looks rather different for different people.

I'm different people, so I can use myself as an example!

Contrary to your advice, if my first drafts aren't already pretty good, I should just throw things out and start over from scratch. When I'm in a creative mode, either I'm not writing in prose, I'm outlining or brainstorming; or what is creative is actually the production of prose-that-might-be-worth-reading, and editing after that verbal creativity is a process sort of like liposuction: yes, in a sense it makes things better, but you also end up with unavoidable scars.

If the body of the text isn't already quite good-looking, going under the knife won't make it so.

Then again, anyone reading my prose has to have a certain concordance of style with me; if they don't, no version of my ideal physique will look good to them. (Why, in God's name, would you put a parenthetical there?! It totally disrupts the flow!) But among those readers who at least potentially could like what I write, the satisfied ones will almost surely have read something I wrote and did not edit very heavily.

I don't mean to say that editing is not essential for me also! Of course it is; it's just that if it's not traversing the path between "oh, pretty good!" and "nice!", the fix isn't editing, it's the rubbish bin.