Why are degrees in arts and humanities not worth investing in?

The Brighter Investment model, an investment in a student's higher education in return for a % of their future income, naturally results in a focus on the brightest students pursuing the degree programs with the best career potential. The consequence of this focus on career potential and income, is that the majority of degrees Brighter Investment supports are programs in science, technology, engineering, medicine as well as certain business and finance degrees. Degrees in art and the humanities are examples of areas that we currently don’t support students in. Why not? And should that change?