Sure, I get what you are saying, but I still think you are wrong here, because I don't think that your sense of "homebrew" is the conventional understanding or usage for the term "homebrew" even when it comes to settings. WotC, for example, does not contrast between official homebrew settings and unofficial hombrew settings in their pollings. It was between the number of people who run official settings versus those who had homebrew settings. It may be helpful for you to say that there is common "core," homebrew, and official settings that may vary the core assumptions. But it seems inaccurate and misleading to call official settings "homebrew."