Manya Whitaker, PhD, Developmental/Educational Psychologist; Assistant Professor of Education; Educational Consultant
Making college free would certainly mean more people would be able to attend, but it doesn't mean that everyone would have equal access to a high quality education. The reality is that private schools have more financial and manpower resource to offer a more extensive academic and social experiment than do public colleges (this is not to say that private colleges are "better"; they just generally have more offerings like study-abroad, money to support unpaid internships, opportunities to research and travel with faculty, etc). People who can afford private school tuition would continue to attend such institutions while others who could not afford private school would likely end up at a free public school.
This becomes problematic because of a trickle-up effect wherein private schools comprise the top institutions in the country and are highly regarded in the labor market. Students from private colleges often get 'scored' higher in graduate school admissions and when applying for jobs (I am not suggesting this is a good or valid practice). These same students then disproportionately enroll in private graduate schools, while students who attended public undergraduate institutions tend to enroll in public graduate schools. When they enter the job market, the academic rankings remain so the jobs students get can look very different depending on the type of institutions they attended (even if they have the same GPA, major, etc.).
So Bernie Sanders' comparison of the U.S. to other countries is not valid. Other countries do not have such a stratified economic or social system that depends on hierarchy to function (the core of capitalism). Giving people access to a college education will not magically make college graduates equal on the labor market. The fact of the matter is that other factors beyond education level play a major role in employment and while Bernie's plan would help mitigate academic differences between people, it would not at all change economic, racial, experiential, language, geographical, or gender differences. And all of those things matter when comparing job applicants.