Perhaps a more productive way to present these ideas would be to mention sources. There’s far too many immersion myths across the Japanese learning communities you find on the internet, and the amount of resources that point to immersion as the end-all of methodologies is certainly big. The myth is so pervasive that you can find views contrary to this belief deemed unpopular opinions.
Luckily for us, this forum is usually both useful and friendly (and not constrained by space!), which means that this is a place for people to expound upon their views instead of making blanket statements that are not of much help.
@NicolasCoutinho does mention an interesting point that many seem to be familiar with: When acquiring English as an L2, there seemed to be a process of immersion that led them to acquiring English at a high degree of proficiency. There is probably a couple of good reasons for that, though: Portuguese and English display high lexical similarity, and their genetic relationship makes English syntax much easier to understand for a Portuguese (or French, Spanish, German, etc.) speaker. Japanese, however, has a much higher entry fee in terms of vocabulary and grammar, if you come from English or any other IE language.
In Japanese learning circles, people seem to advocate for immersion plus mining: Mining is, however, part of the process of building vocabulary. In other words, mining is what does the bridging between immersion and acquisition. If the notion of immersion used for attempting to learn Japanese doesn’t come with the caveat that consumption must be done by building intelligibility, then it seems doomed to fail. On the other hand, when people advocate for immersion, they usually do so in the context of using methods for building intelligibility, such as flashcards.
Anyway, because of the popularity of Anki within said circles, I think that most people who do immersion do so in a semi-structured fashion, not purely through consumption but also through vocabulary building and grammar pattern studies (hence the popularity of lay grammar guides like Tae Kim’s). The real question–as its answer would prove useful for people in the process of learning–is what current pedagogical methods in language education can say about the grammar acquisition process (considering we’re on the Bunpro website).
