Fewer of the people who are currently borrowing would default. That's not the same as fewer people would default. Lower rates will cause more people to take a

Fewer of the people who are currently borrowing would default. That's not the same as fewer people would default. Lower rates will cause more people to take a loan, and you have to think they are the more marginal students. Then you're left with whether it's ok for society to pay for more people trying college and not finishing. A political question of course.