Any degree worth getting can easily repay itself. 1) Get a useful degree, 2) Go to a state school, 3) Quit the narcissist entitlement mentality.
Education has the best ROI, but like any investment you still have to watch how and what you invest in.
There's a rather significant factor you're omitting here though.
When I invest in mutual funds, stocks, or bonds for my traditional "investments", it is a rather emotionless transaction that is truly only tied to the performance I would expect to receive in return. In other words, I'm only doing it for the money, plain and simple.
However, when investing in yourself and your career (one does not endure four years of training for a mere "job"), the other emotional factors come into play, such as work-life balance (e.g. the medical profession), job satisfaction (are you doing what you ultimately want to do in life), and overall happiness (if you love your job, it never seems like work).
Point here is simple. If you offered me six figures to shovel shit out of a cart for 8 hours a day and guaranteed me that job for the next 20 years to ensure it's a career that leads to retirement, chances are I'm still going to be fucking miserable in life. Sure I may have money, but is it ultimately worth it? If you want to be a Philosophy major to achieve happiness in life, then go be one. It might simply be wise to understand what kind of income one would expect and balance that against the training that may be necessary to achieve that happiness. The disgusting part about today's college environment is it's quickly becoming insanely expensive to achieve a degree even in underwater basket weaving.
We invest in traditional investments to make money. We invest in ourselves for a hell of a lot more than that. And if you're not, you'll understand soon enough why it's important to factor it in.