The attrition rate is exactly the point of this. If incoming engineering students were predictably going to be rich, debt financing is the right way to go. If they are a gamble, financiers should take that risk, not the students. If they are not a gamble, because it is easy to predict which ones will succeed, then the financiers will only finance the likely ones and the others will switch fields without wasting a year of their lives.
The attrition rate is exactly the point of this. If incoming engineering students were predictably going to be rich, debt financing is the right way to go. If they are a gamble, financiers should take that risk, not the students. If they are not a gamble, because it is easy to predict which ones will succeed, then the financiers will only finance the likely ones and the others will switch fields without wasting a year of their lives.