There are true risk sharing models that do not involve interest. For example, I want to start a business, instead of taking a interest-bearing loan, I have someone invest in my business in return for equity. This way, risk is shared by both (or more) of us. If the business fails, we both lost effort and money and time. If it succeeds, we both profit.
With lending money, there's usually a collateral involved. If the borrower defaults, then the lender simply comes after his property, taking more than what was originally lent, purely by the passing of time (which accrues interest).
When you read about student loans for instance, especially higher loans for people who go into law or med schools, how even after those people are employed and making good money, their outstanding amounts barely budge (or even accrue) even after a while. This is unjust, unfair, unethical, and exploitative.
