Higher education in the US is hardly about learning the skills for a particular discipline or trade. The American university system is a class differentiation mechanism, and students are paying for access to the managerial professional class, often the highest class one can achieve without family connections.

Even if tuition costs more than can be earned back in wages, it’s still a good investment because the alternative is lower class jobs or unemployment. (There are a few counter examples of professions which pay well and don’t require a university degree).