Writing is Darwinian not Newtonian
You are right about it being Darwinian. Cicero said, "The rules follow from eloquence, not the other way around." Good rhetoric is what works, what fits the purpose.
I completely agree with you. In fact, one of the things the best teacher I've ever had taught me is precisely to adapt my writing to the circumstances. To write in whatever way is best for the story in question and to take into account that I can't always apply what I've learned from writing it to the next thing I write.
"better writer than he" (not "better writer than him"). And please remove me from this list.
Seems to me a lot of your criticisms of Orwell are answered in the essay his rules came from. For example, he acknowledges you can follow his rules “and still write bad English”, and that they don't apply to literary writing.
Speaking as an editor, most of the pieces I've worked on were better after Orwell’s rules were applied. You can improve a lot of writing just be cutting the flab.