Mostly because of accessibility. Danish universities, while being free, are much less accessible than the U.S and also lower than the OECD average: https://nce

Mostly because of accessibility. Danish universities, while being free, are much less accessible than the U.S and also lower than the OECD average: https://nces.ed.gov/programs/coe/indicator/cac https://nces.ed.gov/programs/coe/indicator/cac