I disagree that a scholarship is the only way to earn achieve social mobility.

A college degree is a necessary but not sufficient condition for breaking into the middle class. If a loan can help someone meet that condition, great.

This is not to say that colleges aren't horribly overpriced (they are) or that more scholarships shouldn't be available (they should, including government grants; one of the best long-term investments in the economy the government can make).