re: At least half of students defaulted or failed to pay down debt within 7 years

The DOE makes it near impossible to discharge a federal student loan simply because there is nothing of value they can legally get back from doing so. In a traditional bankruptcy, a bank could take possessions, sell them, and recoup some or all of what is owed. The DOE can't repossess an education, because it is a service and is considered a sunk cost. Same way they can't take back all the nights of partying done on the government's dime.