It does outside the English-speaking world. In many non-English-speaking countries—including Japan, where I live—English education is similar to mathematics education: All children have to study it and ability at school English is treated as an indicator of overall academic ability, but many children struggle with it and by adulthood most people have forgotten most of what they learned.
In Japan, school English education is also affected by problems similar to those mentioned in other comments on this page, including English teachers who themselves are not skilled at the language, educational policies that require that all children study the same material at the same age, and, sometimes, an overemphasis on rote memorization and teaching-to-the-test.
There’s a huge industry in Japan serving adults who have forgotten most of their school English—or didn’t learn much in the first place—and who now want to get better at it in order to advance their careers.
I took several years of Latin in both high school and college but outside of those academic environments I never had cause to use it and while I remember a lot of aspects of it structurally, my Latin vocabulary is almost all gone. I have at times pulled out my old textbooks just to try and see what I can do, and I can certainly work through that material a lot faster than the first time around, but I’m still needing to start at a rudimentary level to get anywhere.