Maybe not everyone, but certainly lots of unethical people would do it, and there are lots of those. They'd post unbearably smug posts on LinkedIn about it too, calling everyone a sucker who didn't walk away from their $200k in student loans via bankrupcty.

The justification for student loans being exempt from bankruptcy is simply that there is no asset to be repossessed. Car loans, mortgages, and HELOCs are different. Credit cards have very high interest to pay for the higher risk. I guess we could have student loans with 29% interest, would that be preferable?

You could have free education, for instance. I think that would be preferable to any sort of student loans.