OK, but you’re moving the goalposts. A written form of the language curated specifically for the purpose of learning is not really relevant to a discussion of the language, just as would be the case for any other language. That is not the language used in daily life. There are no furigana in a newspaper or on the Internet (technological assistance notwithstanding). Magazines, business communication…anything useful is off limits if you can’t read, say, 500 kanji at an absolute minimum. Anything more advanced, academia, etc. requires far more.