Why are German and French taught in so many schools when their native speaker counts are so much lower than other languages? Are we going by economic importance

Why are German and French taught in so many schools when their native speaker counts are so much lower than other languages? Are we going by economic importance? Then why isn't Mandarin just an assumed course at every high school? I know lots of schools are starting to pick up on this, but it seems like it still viewed as a special thing. Kids should be far more computer literate than they are now. People understand basic biology, chemistry, etc, but almost no one I know outside of work could give you even a rough abstraction of how a computer works (except maybe the idea that there is "memory" and the "cpu" is the thing that does the work). I could rant about this topic forever, the state of high school education in our country is absolutely atrocious. I learned way more from reading in high school than I did in class (save my Chemistry teacher who was awesome).