Putting aside the fact my example of partaking in a political process inherently implies being able to digest and express opinion on political issues (not sure what tv has to do with it), at this point it just seems like you're being needlessly contrarian - or don't understand Zefah and I were talking about cultural fluency being a large part of linguistic fluency. Your examples seemed to focus on insanely advanced displays of technical knowledge or industry knowledge.
99% of people in any country could not write a 'publishable essay or thesis with very minimal edits required.' Japanese, German, British, whatever. This is a skill acquired through actual academic experience and is something people specifically dedicate their studies to. It's a skill that can enhance and exhibit your cultural or linguistic fluency, but is not something inherent to native language use. So I guess the majority of natives in a culture are not fluent.
Selling yourself or services is an actual technical skill taught in schools, taught in businesses, and learned through life. 99% of people in any country don't know how to properly sell an idea, service, product, or themselves. That is why the position of sales exists. This has nothing to do with cultural or linguistic fluency, it something you can layer on top of those two things to make yourself advanced in a specific field. So I guess the majority of natives in a culture are not fluent.
I'm not trying to purposely be obtuse, I get what your point is, I just think you're purposely stretching your examples to some how show that they require more fluency. They require more technical knowledge, not fluency.
I have actually seen this argument a lot in the real world. Someone tries to defend their language skill by saying something like 'I'm more fluent than that guy, I translate legal documents!' Translating legal documents is surely an advanced skill, but it has nothing to do with fluency. I could hand a 45 year old bank manager a legal document in their native language right now and they would have no clue whatsoever how to interpret it other than (and maybe not even with 100% accuracy) being able to verbally read it out loud. They're not fluent I guess.