Why would anyone want to go $100-200K in debt to end up working at a research university for a $30K stipend?
Exactly the problem. There is another aspect of this that I find very distasteful. Universities keep accepting people into their PhD programs even though they know there are no jobs for them. They do this because they need the warm bodies - to do work for the NIH-sponsored investigators, to justify the training grants the institution has, and to maintain the stature of the university as a graduate degree granting program.
I've seen a fair number of bright, energetic, and sincere people really hurt themselves by spending 4-6 years in a lab struggling to earn their PhD, so that they could then go out and do a 2-4 year post-doc working nights and weekends to get some papers out, so that they could maybe get an offer as junior faculty on soft money, and hope that they could be one of the lucky ones that received an NIH grant (currently around 6-8% of applications are funded).
Compare that to the people who run cleaning or lawn care services around where I live, and make six-figure salaries with much of it under the table and thus not taxed.