For a clear picture of how damaged the US postsecondary education system is, one need only look at the money-printing mill that is the for-profit college. I should know: I spent 10 years “teaching” at one of the most notorious cash-grab colleges in the country. There, I saw profoundly underprepared students racking up far more debt than their “traditional” peers – debt they would default on at more than twice the rate of those peers, landing the costs of these wayward scholars directly on the shoulders of taxpayers.

This week, the US Department of Education accidentally showed just how badly the problem of for-profit college debt is intertwined with predatory loan collection: in a court filing, the Department of Education jacked up its estimate of its own illegal debt collection from 16,000 former students at bankrupt Corinthian College to nearly three times that amount. All while the secretary of education, Betsy DeVos, who was held in contempt of court for the department’s actions, continued to refuse debt forgiveness for thousands of students ripped off by for-profit colleges.

From 1995 to 2015, enrollment at for-profit colleges went up more than 460% – more than 14 times that of traditional institutions. Meanwhile, students at for-profit colleges – mostly low-income, minority or first-generation college students – face challenges that severely compromise their ability to stay in school: my students suffered from homelessness, mental illness, abuse and bank accounts so low they couldn’t afford subway passes.

Those challenges didn’t matter to recruiters: skipped the SAT or ACT? No problem! As long as you had a pulse and a GED you were in. Once those students got to class we professors – whose yearly fire-at-will contracts made us particularly vulnerable to any kind of student complaint – were told to “work it out”.

The students got the message: they considered us waiters, essentially, and complained constantly about our bad service. Their mantra was “the customer is always right”, and the administration agreed: I got hauled in front of my department chair for such extreme professorial misconduct as pointing out to a student that she was late to class; for asking students to print their syllabi; and for having the gall to assign them actual work.

Despite this, professors toiled mightily to educate their students, even if that meant helping them find housing, childcare and jobs. More than once I slipped students extra cash to make sure they could eat. All of this was met with a shrug from the administration, who on one memorable “Faculty Appreciation Day” gifted us a handful of whiteboard markers – otherwise free in the supply closet – festooned with ribbons.

Considering the challenges they faced, some students worked heroically. One of my students, who had contracted HIV after being forced into prostitution as a young girl, battled manic depression to become a case worker at a men’s shelter. Others sweated through classes grasping their desks for anchor, they were so traumatized with PTSD from their military days.

But for most the future seemed grim. They simply could not balance their difficult circumstances and their utter lack of preparation for college-level work. Nearly 80% of students at for-profit institutions nationwide won’t graduate.

Those who do graduate don’t fare much better, as my LinkedIn feed attests: “security consultant” (guard), “customer interaction manager” (sales clerk) and “Assistant Manager at Old Navy” are OK jobs, but they needn’t have cost these students the more than $48,000 that they did.

In 2004, Barack Obama tried to address this with the gainful employment rule, forcing for-profits to prove their graduates could find good jobs in order to be eligible for government financial aid. When Trump won in 2016, you could almost hear the champagne corks popping in for-profit college administration offices; Trump appointee DeVos wasted little time in undermining the Obama rule before finally officially repealing it earlier this year.

There are better ways to fix the problem. Increasing investment in public universities and especially in public two-year colleges and technical schools would be a good start. But really we should be investing in the places these students go before college, and that means bridging the $23bn funding gap between majority-minority schools and their majority-white counterparts, who serve the same number of students. College prep cannot start in college.

More to the point, we should be reframing the system entirely: is a bachelor’s degree really necessary for young people to join the fastest-growing US job sectors, those of technicians, assistants and aides? And how many students really want that bachelor’s? Every student should be able to get the education they desire, but the bulk of mine had no interest in a classical education: they wanted to get their diploma and get out.

Recently, strong job numbers have hurt for-profit enrollment – fewer out-of-work adults means fewer adult learners returning to school. But there are over one million students currently enrolled in for-profit colleges. They’ll learn the hard way that, when it comes to a college degree, the adage “you get what you pay for” couldn’t be further from the truth.