Everyone coming up with conspiratorial reasons why this is not the case but it’s much simple than that. It’s not feasible and it’s expensive and the returns aren’t really worth it.

Kids in school have a bunch of other subjects they have to learn besides foreign languages. You can add one or two languages but then at some point you will need to remove other subjects to add more or you need to keep kids in school even more. Both are not really feasible. Then you need to hire teachers for all these new languages which most places won’t do.

Another issue is with the way they teach languages in schools. They expect you to pass a test and not actually learn the language so a lot of the languages will not “stick” as the students lack immersion and practice with that language. I can speak for myself, I have learned two languages besides my native language in school: French and English. I had French since 2nd grade, which is 10 years of French classes and English since 5th grade which is 7 years of English classes. Today I can speak English fluently and like 3 words of French. The difference was that I was always immersed in English, though video games, movies, songs and so on. Not so much with French. I have noticed the same pattern with most of my friends and family members.