So while student loans were technically dischargeable approx 28 years ago there were some big caveats.
Fact: they were dischargeable. Fact: there was no crisis else rates would have already factored in. Else the argument is they were losing money overall. They wouldn't do that for literal decades. Fact: after the loans were no longer dischargeable, banks were guaranteed their rates and stopped being competitive with them and rates increased.
Loans are still dischargeable under certain conditions.
You claimed that "a quarter century ago" student loans could be discharged in bankruptcy, but that's not really true either. The restrictions started in 1978 with waiting periods and those waiting periods were eliminated in 1998 for government loans and shortly after that for private loans.
The period in which you got this 4% loan was within the period where bankruptcy protections were in place, not before it.
You are simply misremembering. If it’s true, scan and upload the loan agreement. I just don’t believe it based on how lenders operate.