So I would have to ask that once they've gotten through to grad school, how is money a hindrance when they can earn money while pursuing the degree?
Because stipends are rather low. It's enough to live off of, but it's not enough to lead an upper middle class lifestyle once you graduate. Also, I think that you are actually in a better position to make use of your degree since you have prior work experience. For a lot of people with Ph.D.'s, they have been in school since age five, and have been surrounded by other people that have been in school since age five so getting a job is something of a shock.
One good thing about the Ph.D. however is that you leave with zero debt, which turns out to be a tremendous advantage. If you get a physics Ph.D. and you want to be a beach bum, you can do that. If you get a law degree, you can't, because, you are in debt up to your ears.