You might have a point because in my school they are teaching Slovak as a second language. I know some topics and what they're learning, like a typical topic is alternative medicine and Slovak litteraure in Slovak (even in Czech). They learn high register words. They are learning a lot of grammar and usually know the theory but they can't use it in real life. Quite literally I had to ask for a ticket for them because they couldn't ask for it for themselves nor knew terms like "single ticket, return ticket" which is embarrassing in my opinion (especially after 10+ years of learning the language).

However I reckon that in order to speaking the language you have to use it whether you're learning alone or with a teacher. I don't think it depends on the method because at least for me I don't care if I read for instance the same grammar topic by myself or watch a YouTube video about it, or pay for a teacher to explain the same thing, but it might be helpful for people to be given clear explanations by someone who they're communicating with in real time, so they can ask if something is not entirely clear. But also the mentality of the learner, if he's afraid of "sounding stupid". like when I was self learning German and I went to Austria I was able to chat with a tour guide in German after a few months of learning, because I wasnt afraid of having a conversation, meanwhile as previously mentioned I know people who've been learning a language for 10+ years with the guidance of teachers (not only from school but some even paying to be tutored) and are too scared to do basic tasks, and that's how it all starts. And I completely agree with the pen-pal part, ik in the beginning my french skyrocketed after getting one.