History of economics disagrees with the last -- hopeful I will assume -- statement. The world was and is full of scammers and fraudsters.
Also respectfully I am not sure I get the zero interest rates arguments. There seems to be a subgroup of HN community that believes low interest rates (below some arbitrary threshold?) to be immoral. Maybe there is a Crime, scams and ponzi schemes correlation study over hundreds of years I am unaware of? Japan is keeping negative rates and they are not known for that, to give the country everyone knows counterexample.
Besides that the main borrowers are countries themselves. And with US, Europe and China paths right now, amidst a global war tension, something will have to give long term to make ends meet. Usually it is currency devaluation and a fundamental systemic change.