[TimPC]

Math education is the second highest paid undergrad in arts and science and was number one ahead of CS for a long-time. Many people with math degrees end up in high paying technology or statistics jobs. Math is both an incredibly marketable skill and the program often indirectly selects for high IQ which is correlated with success to a certain degree. You generally aren't going to do abstract algebra or topology for a career unless you are a math professor but being good at abstract algebra or topology generally requires a lot of skills that are useful in the labour market.

As for the main point, I think the best form of education for something does depend on what the outcomes are. If you're getting a degree that doesn't qualify you pay back the costs of that education maybe alternative methods have better outcomes (we'd accept a decrease in educational attainment for cost). If being a small amount better at something is lucrative we should optimize for performance more than cost.