Yeah - I think the reason is twofold.
First, this method doesnt really fit into the traditional classroom setting very well - people will learn the language over time using this method, but will learn different things at different speeds. You can’t test people on vocab and grammar if their assigned work is simply “listen to these people speak and try to understand the gist”. So you can find private instructors who use these methods (and in other countries, it is the default method for teaching english) - but in schools or government-sanctioned courses, it would never fly.
Second, people want to speak. Actually speaking the language and having a conversation in it is what they feel like progress should look like. So when you tell them that they won’t speak the language until they have consumed something like 1000 hours of content, they tend to write the method off. This is especially true if they have a deadline to meet - like they want to learn a language before a trip to another country. But really, in that case, you should simply get a traveller’s phrasebook and memorize a few phrases. You probably won’t make meaningful progress in learning a language in 4 weeks (or whatever) before your trip anyway.













I mean, if you want to learn spanish, try dreaming spanish.
For Japanese - iirc, Tandem has a paid tier where it will show you people who are nearby you? So maybe try finding some Japanese speakers near you, and pitch crosstalk to them. Maybe one or two will become consistent language learning partners, and you’ll make friends in addition to learning Japanese.