well anecdotally from studying Japanese for about a year and a half before moving there, it seems right to me, in particular the part about conscious effort not being able to produce spontaneous speech.

I was embarrassed how little I could say after countless hours of flash cards and other methods. I'd literally just comprehend nothing if someone talked to me. But after a few months of just listening it became much easier. I've thrown all the Anki cards away afterwards, it was just a waste of time.

I realised a step up with going to lunch with Japanese friends where the stream of sounds started to become comprehensible as discrete words. When I understood some of them I at least grasped the topic of the conversation, though not the details. It takes time and patience...

It definitely wasn’t a waste of time! I passed JLPT N1 back in 2014 after ~6 years of mostly Anki-based studying. Did Heisig’s RtK first and then mostly played old Japanese console games that I was familiar with. Never opened a JLPT study guide and passed the test on my first attempt.

Could I speak Japanese at that point? No not really… I even had a Japanese spouse! But we spoke mostly English at home. I could read quite well, but conversation was very challenging.

Then we moved to Japan. Despite not having a job that requires me to speak Japanese, I got enough live exposure just from chatting with people at the gym or in social activities that now, a few years later, I’ve backfilled all that conversational fluency that was missing. No special extra effort required, just living in an environment where I used the language reasonably often.

Anyways, the point is that all the time spent in Anki laid a rock-solid foundation that merely needed activation in the right environment for active fluency to emerge. Of course I no longer do my daily flashcard drills (and I’ve forgotten how to write quite a few kanji as a result) but the work paid off.

Anecdotally, yes.

I have learned a lot of languages, and the method that worked best for me was to read books in which I was interested and to watch movies spoken in that language that were interesting, with the periodic help of a grammar and a dictionary.

Traditional language handbooks or other simplified sources have not been as useful as being exposed to a great amount of non-simplified language, which I reread and rewatched until I understood it perfectly.

It was essential for the books that I read and the movies that I watched to be good enough, so that I really wanted to understand what was written or said.

Even in the beginning, I did not use the grammar and the dictionary very frequently, especially with movies, but I attempted to guess the meaning of the unknown words and move forward with the reading or watching, without interruptions. Only later I confirmed or rejected my guesses with the grammar and dictionary.