Undergrad students are limited to $31k or $57.5k in federal loans (including only $23k of subsidized loans) depending on whether they are a dependent or not. [1] That is still not enough for many students to attend their college of choice.

I will admit I chose the wrong word in my prior comment when I said guaranteed since that has a very specific meaning in this context. I was using that phrase more colloquially because there are other ways that the government protects the lender beyond a literal guarantee. For example, student loan debt cannot be discharged in a bankruptcy like mortgages, medical debt, or credit card debt. This was done because a private lender is normally heavily disincentivized from loaning money to someone with no credit history, no collateral, no income, and no expectation to start making payments on the loan for years.

[1] - https://studentaid.ed.gov/sa/types/loans/subsidized-unsubsid...