In most other countries, student loans aren't even a thing, because university is subsidized to the extent that it is free or relatively inexpensive. The size of the bet is absolutely integral to whether giving the loan makes sense, because it affects the benefit of discharging the loan. If you're saying, "We should make uni cheap or free, and also make loans dischargable," well, sure, but now you're talking about changing a lot of variables rather than just one, and correspondingly increasing the difficulty of reform.