Good writing may simply be arbitrary—a product of social consensus. Some artists that are now considered good (like Van Gogh) where ignored during their lifetime. If this is the case, then perhaps it is a mistake to talk about mastery in the first place.
There are certain guidelines of good writing that seems to make sense. It makes sense that they are widely accepted. Most of the are technical in nature, which when executed makes reading easier.
But guidelines about style, processes, how to live your life as a writer, topics—these are all purely subjective.
References
Young, S. (2019, August 26). How Should I Get Better at Writing? Scott H Young. https://www.scotthyoung.com/blog/2019/08/26/better-writing-brainstorm/