It wouldn't be half the country first of all. It's a small minority of adults having problems paying their student loans (mostly those that were wildly reckless in their easy borrowing). The median student loan is a mere ~$13,000, against a median full-time wage of nearly $50,000.
If you took out $250,000 in student loans for a career path that pays $65,000 max per year, that's on you for being so financially foolish. It's not difficult to look around at cost effective alternatives to such a crazy student debt load.
You can easily go to extremely high quality in-state public universities at a modest cost. A four year degree in the US will get you a $60,000 salary on average right out of school. The typical person holding the median full-time job making $50,000, does not even have a four year degree. After five to seven years in the job market, your income is going to be $75,000 or more. You can do better than that in engineering fields. The unemployment rate with a four year degree, is typically about half the national U3 level, you practically can't not be employed.
Here's the fact of the matter: US wages are so extraordinarily high, a four year degree is a steal, just so long as you don't do something crazy like take on $200k in debt for a path that can never pay a good wage.
Go to an in-state public university, pay $10,000 to $15,000 per year net (a part-time job, as was very common in decades past, is still a good idea, along with seeking grants), get a job making $60,000 and work your income up to closer to $75,000 to $90,000 over time. That student debt becomes meaningless. It is not complex.