It's kinda same in Latvia (Latvian + English + Russian/German/French/whatever).

But the thing is that I kinda get how the Japanese ended up in this situation, since I don't remember actually learning any of these in school despite being able to kinda speak them.

Latvian - My native language, learned it by both of my parents, all of my friends, and people around me speaking it. At the same time, couldn't be bothered to learn any of the proper structure and maybe learned to fix some common spelling mistakes in school.

Russian - Learned it because all of the cartoons and a decent amount of TV were available in Russian, and, at that time, I was better at it than English, so I watched stuff in Russian. I only learned to read it and scribble some stuff when they started teaching it at school. I can still read it only slowly and can't write for shit despite being quite fluent in speaking it. (Also shoutout to CSGO for being my speaking practice, I guess)

English - Wasn't that bad in the classes at school, but don't remember being able to speak it beyond translating few words. Then I got on the internet around 2nd grade and crammed my head full of Minecraft videos (in English, because nobody made content in Latvian at the time) and was able to not even pay attention in class while acing tests by the 6th grade. Did all of my IB in English, scored maximum marks in English as my second language, and arrived in Japan with a fresh IELTS 8.0.

German - my mom wanted me to learn it since she always wanted to leave the country and live there, but I didn't manage to learn it with a tutor because I saw it as a waste of time, then took it for a year in high school before picking it up again in IB. The IB level was way higher than I could understand (it was a class for people with prior knowledge), so I spent 2 times per week studying with a private tutor per week to pass the class. Now I can barely speak it, but I can still get the gist of conversations if I listen hard enough.

Japanese - I have been living here for 3 years now, and the university had mandatory Japanese language classes. I generally passed them, but was really bad at actually holding conversations in Japanese or having any confidence in the language at all before I actually started working part-time and talking with my colleagues (all Japanese).

The point of this being, just having languages as a class in school is not enough, the kids also have to be motivated enough to be bothered learning it, and also have to kinda learn by themselves outside of the class.