I hear your point, but neither Princeton nor Yale require students to get loans. Along with a number of other super-prestigious schools, they offer all students full grant coverage of all the cost they can't afford.

"By committing to an admissions policy that does not consider a student’s ability to pay, and by meeting the full financial need of all admitted students (with no loans required), we ensure that Yale is accessible to the most talented students from around the world, regardless of their family’s income" http://admissions.yale.edu/financial-aid-prospective-student...