I don't think GP's surprise was based on the idea that a bachelor's degree in such a major would typically be cheaper than others. I think GP was surprised that someone would be willing to take on so much debt for a degree in that major.
It's 25K-26K per year, so even if she paid nothing out of pocket and had no financial aid, she'd owe slightly over $100K when she was done. And the rest of it has compounded.
But yeah, most people don't do the math and don't have a realistic view of their career path when they enroll in their programs. I think depression would be a lot more common, if they did...
The best advice is to pay the minimum you can unless you get a shot at going to harvard. And if you do, some of these school now are offering free tuition for people making less than X amount of money.
I might be biased because I have a degree from a state university but that never prevented me from getting work.
Seriously, though, in most schools tuition is the same regardless of the major. I hear it's $40K+/year for tuition alone at many private schools.