The theory of writing is ultimately founded upon understanding the rules of the language (be it English, Spanish, German, et cetera). As by understanding the rules does one begin to understand how to break the rules.
Think about it like this: While Hemingway and James Joyce have distinct writing styles (especially James Joyce in his book titled "Ulysses"), both understand how to use the English language to their advantage. Hemingway's style is straightforward and often easy enough to read for people whom English isn't their native language. However, it is by analyzing his work that reveals further details and things that may not be obvious the first time you read his work. On the other hand, James Joyce's style in "Ulysses" seeks to closely emulate actual human thought ("stream of consciousness").
But as your question on the relationship side of things, the knowledge created is both a byproduct and catalyst of the theory of writing. As by writing, you will find that you may need to expand further on your theory of writing.
For example: While making an outline may come off as time consuming, the feedback you get from people you have asked to read could be that the story is hard to follow or confusing. But when you go through the effort of doing an outline and using it to aid your writing, you might get a better response on how it's easier to understand and flows better.
Thus, it is a cycle. You make a rough draft and then edit & revise whilst getting feedback on how to improve it. This relationship is one in which constant effort furthers knowledge and fuels the desire for more.
